G2Cdb::Gene report

Gene id
G00002104
Gene symbol
ATP1A2 (HGNC)
Species
Homo sapiens
Description
ATPase, Na+/K+ transporting, alpha 2 polypeptide
Orthologue
G00000855 (Mus musculus)

Databases (8)

Curated Gene
OTTHUMG00000024080 (Vega human gene)
Gene
ENSG00000018625 (Ensembl human gene)
477 (Entrez Gene)
413 (G2Cdb plasticity & disease)
ATP1A2 (GeneCards)
Literature
182340 (OMIM)
Marker Symbol
HGNC:800 (HGNC)
Protein Sequence
P50993 (UniProt)

Synonyms (1)

  • FHM2

Literature (77)

Pubmed - other

  • Isoform specificity of cardiac glycosides binding to human Na+,K+-ATPase alpha1beta1, alpha2beta1 and alpha3beta1.

    Hauck C, Potter T, Bartz M, Wittwer T, Wahlers T, Mehlhorn U, Scheiner-Bobis G, McDonough AA, Bloch W, Schwinger RH and Müller-Ehmsen J

    Laboratory of Muscle Research and Molecular Cardiology, Department of Internal Medicine III, University of Cologne, Cologne, Germany.

    Cardiac glycosides inhibit the Na(+),K(+)-ATPase and are used for the treatment of symptomatic heart failure and atrial fibrillation. In human heart three isoforms of Na(+),K(+)-ATPase are expressed: alpha(1)beta(1), alpha(2)beta(1) and alpha(3)beta(1). It is unknown, if clinically used cardiac glycosides differ in isoform specific affinities, and if the isoforms have specific subcellular localization in human cardiac myocytes. Human Na(+),K(+)-ATPase isoforms alpha(1)beta(1), alpha(2)beta(1) and alpha(3)beta(1) were expressed in yeast which has no endogenous Na(+),K(+)-ATPase. Isoform specific affinities of digoxin, digitoxin, beta-acetyldigoxin, methyldigoxin and ouabain were assessed in [(3)H]-ouabain binding assays in the absence or presence of K(+) (each n=5). The subcellular localizations of the Na(+),K(+)-ATPase isoforms were investigated in isolated human atrial cardiomyocytes by immunohistochemistry. In the absence of K(+), methyldigoxin (alpha(1)>alpha(3)>alpha(2)) and ouabain (alpha(1)=alpha(3)>alpha(2)) showed distinct isoform specific affinities, while for digoxin, digitoxin and beta-acetyldigoxin no differences were found. In the presence of K(+), also digoxin (alpha(2)=alpha(3)>alpha(1)) and beta-acetyldigoxin (alpha(1)>alpha(3)) had isoform specificities. A comparison between the cardiac glycosides demonstrated highly different affinity profiles for the isoforms. Immunohistochemistry showed that all three isoforms are located in the plasma membrane and in intracellular membranes, but only alpha(1)beta(1) and alpha(2)beta(1) are located in the T-tubuli. Cardiac glycosides show distinct isoform specific affinities and different affinity profiles to Na(+),K(+)-ATPase isoforms which have different subcellular localizations in human cardiomyocytes. Thus, in contrast to current notion, different cardiac glycoside agents may significantly differ in their pharmacological profile which could be of hitherto unknown clinical relevance.

    Funded by: NIDDK NIH HHS: R01 DK057678

    European journal of pharmacology 2009;622;1-3;7-14

  • Familial hemiplegic migraine is associated with febrile seizures in an FHM2 family with a novel de novo ATP1A2 mutation.

    de Vries B, Stam AH, Kirkpatrick M, Vanmolkot KR, Koenderink JB, van den Heuvel JJ, Stunnenberg B, Goudie D, Shetty J, Jain V, van Vark J, Terwindt GM, Frants RR, Haan J, van den Maagdenberg AM and Ferrari MD

    Epilepsia 2009;50;11;2503-4

  • Isoform specificity of the Na/K-ATPase association and regulation by phospholemman.

    Bossuyt J, Despa S, Han F, Hou Z, Robia SL, Lingrel JB and Bers DM

    Department of Pharmacology, University of California, Davis, California 95616, USA.

    Phospholemman (PLM) phosphorylation mediates enhanced Na/K-ATPase (NKA) function during adrenergic stimulation of the heart. Multiple NKA isoforms exist, and their function/regulation may differ. We combined fluorescence resonance energy transfer (FRET) and functional measurements to investigate isoform specificity of the NKA-PLM interaction. FRET was measured as the increase in the donor fluorescence (CFP-NKA-alpha1 or CFP-NKA-alpha2) during progressive acceptor (PLM-YFP) photobleach in HEK-293 cells. Both pairs exhibited robust FRET (maximum of 23.6 +/- 3.4% for NKA-alpha1 and 27.5 +/- 2.5% for NKA-alpha2). Donor fluorescence depended linearly on acceptor fluorescence, indicating a 1:1 PLM:NKA stoichiometry for both isoforms. PLM phosphorylation induced by cAMP-dependent protein kinase and protein kinase C activation drastically reduced the FRET with both NKA isoforms. However, submaximal cAMP-dependent protein kinase activation had less effect on PLM-NKA-alpha2 versus PLM-NKA-alpha1. Surprisingly, ouabain virtually abolished NKA-PLM FRET but only partially reduced co-immunoprecipitation. PLM-CFP also showed FRET to PLM-YFP, but the relationship during progressive photobleach was highly nonlinear, indicating oligomers involving >or=3 monomers. Using cardiac myocytes from wild-type mice and mice where NKA-alpha1 is ouabain-sensitive and NKA-alpha2 is ouabain-resistant, we assessed the effects of PLM phosphorylation on NKA-alpha1 and NKA-alpha2 function. Isoproterenol enhanced internal Na(+) affinity of both isoforms (K((1/2)) decreased from 18.1 +/- 2.0 to 11.5 +/- 1.9 mm for NKA-alpha1 and from 16.4 +/- 2.5 to 10.4 +/- 1.5 mm for NKA-alpha2) without altering maximum transport rate (V(max)). Protein kinase C activation also decreased K((1/2)) for both NKA-alpha1 and NKA-alpha2 (to 9.4 +/- 1.0 and 9.1 +/- 1.1 mm, respectively) but increased V(max) only for NKA-alpha2 (1.9 +/- 0.4 versus 1.2 +/- 0.5 mm/min). In conclusion, PLM associates with and modulates both NKA-alpha1 and NKA-alpha2 in a comparable but not identical manner.

    Funded by: NHLBI NIH HHS: HL-30077, HL-81526, R01 HL030077, R01 HL064724, R01 HL092321, R01 HL092321-01A1, R01 HL106189, R37 HL030077; NIBIB NIH HHS: K01 EB006061, K01 EB006061-03

    The Journal of biological chemistry 2009;284;39;26749-57

  • Association between sodium- and potassium-activated adenosine triphosphatase alpha isoforms and bipolar disorders.

    Goldstein I, Lerer E, Laiba E, Mallet J, Mujaheed M, Laurent C, Rosen H, Ebstein RP and Lichtstein D

    Department of Physiology, Institute for Medical Research, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel.

    Background: The sodium- and potassium-activated adenosine triphosphatase (Na+, K+-ATPase) is a major plasma membrane transporter for sodium and potassium. We recently suggested that bipolar disorders (BD) may be associated with alterations in brain Na+, K+-ATPase. We further conjectured that the differences in Na+, K+-ATPase in BD patients could result partially from genetic variations in Na+, K+-ATPase alpha isoforms.

    Methods: To test our hypothesis, we undertook a comprehensive study of 13 tagged single nucleotide polymorphisms (SNPs) across the three genes of the brain alpha isoforms of Na+, K+- ATPase (ATP1A1, ATP1A2, and ATP1A3, which encode the three alpha isoforms, alpha1, alpha2, and alpha3, respectively) identified using HapMap data and the Haploview algorithm. Altogether, 126 subjects diagnosed with BD from 118 families were genotyped (parents and affected siblings). Both individual SNPs and haplotypes were tested for association using family-based association tests as provided in the UNPHASED and PBAT set of programs.

    Results: Significant nominal association with BD was observed for six single SNPs (alpha1: rs11805078; alpha2: rs2070704, rs1016732, rs2854248, and rs2295623; alpha3: rs919390) in the three genes of Na+, K+-ATPase alpha isoforms. Haplotype analysis of the alpha2 isoform (ATP1A2 gene) showed a significant association with two loci haplotypes with BD (rs2295623: rs2070704; global p value = .0198, following a permutation test).

    Conclusions: This study demonstrates for the first time that genetic variations in Na+, K+-ATPase are associated with BD, suggesting a role of this enzyme in the etiology of this disease.

    Biological psychiatry 2009;65;11;985-91

  • Impaired plasma membrane targeting or protein stability by certain ATP1A2 mutations identified in sporadic or familial hemiplegic migraine.

    Tavraz NN, Dürr KL, Koenderink JB, Freilinger T, Bamberg E, Dichgans M and Friedrich T

    Technical University of Berlin, Institute of Chemistry, Berlin, Germany.

    Mutations in three different genes have been implicated in familial hemiplegic migraine (FHM), two of them code for neuronal voltage-gated cation channels, CACNA1A and SCN1A, while the third encodes ATP1A2, the alpha(2)-isoform of the Na(+)/K(+)-ATPase's catalytic subunit, thus classifying FHM as an ion channel/ion transporter disorder. The Na(+)/K(+)-ATPase maintains the physiological gradients for Na(+) and K(+) ions and is therefore critical for the activity of ion channels and transporters involved in neurotransmitter uptake or Ca(2+) signaling. Diverse functional abnormalities have been identified for disease-linked ATP1A2 mutations, which reach far beyond simple loss-of-function. We have shown recently that ATP1A2 mutations frequently lead to changes in the enzyme's voltage-dependent properties, kinetics or apparent cation affinities. Here, we present functional data on a so far uncharacterized set of ATP1A2 mutations (G301R, R908Q and P979L) upon expression in Xenopus oocytes and HEK293FT cells, and provide evidence for a novel pathophysiological mechanism. Whereas the G301R mutant was inactive, no functional changes were observed for mutants R908Q and P979L in the oocyte expression system. However, the R908Q mutant was less effectively expressed in the plasma membrane of oocytes, making it the first missense mutation to result in defective plasma membrane targeting. Notably, the P979L mutant exhibited the same cellular expression profile as the wild-type protein, both in Xenopus oocytes and in transfected HEK293FT cells grown at 28 degrees C, but much less P979L protein was found upon cell growth at 37 degrees C, showing for the first time that temperature-sensitive effects on protein stability can underlie ATP1A2 loss-of-function.

    Channels (Austin, Tex.) 2009;3;2;82-7

  • FHM3 in familial hemiplegic migraine is more resistant to mutation than FHM1 and FHM2.

    Wiwanitkit V

    Wiwanitkit House, Bangkhae, Bangkok, 10160, Thailand. wviroj@yahoo.com

    Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura and transient hemiplegia. CACNA1A (FHM1) gene, the ATP1A2 (FHM2) and the SCN1A (FHM3) are reported for their correlation to FHM. Here, a bioinformatics analysis was done to study the risk positions for mutation within the amino acid sequence of the three mentioned molecules. In this work, the author can identify many mutant prone positions within the studied FHM. Of interest, the author detected that FHM3 is a high resistant molecule when compared to FHM1 and FHM2.

    Journal of the neurological sciences 2009;277;1-2;76-9

  • [Association of the polymorphisms of sodium transport related genes with essential hypertension].

    Gong PY, Shen GM, Peng HM, Luo Y, Shen Y and Zhao X

    Department of Medical Genetics, Medical College, Henan University of Science and Technology, Luoyang, Henan, 471003 PR China. gpy1026@163.com

    Objective: To investigate the association of the polymorphisms of rs4961 in alpha-adducin (ADD1) and rs28933400 in Na+/K+ -ATPase a2 (ATP1A2) genes, the products of which are important for sodium transport, with essential hypertension.

    Methods: Mutagenically separated PCR (MS-PCR) was used to detect the genotypes of the two loci. The subjects were recruited randomly including 196 patients of essential hypertension and 192 healthy controls.

    Results: The frequencies of genotypes and alleles of in the ADD1 gene were significantly different between the patients and controls respectively (P=0.03, P=0.04). There was significant relationship between the genotypes of rs4961 and systolic blood pressure and blood sodium concentration. However, there was no significant relationship between the rs4961 genotypes and diastolic blood pressure, body mass index, blood kalium and chlorine concentrations. There was no polymorphism at the rs28933400 locus in the subjects analyzed.

    Conclusion: The rs4961 polymorphism of the ADD1 gene is associated with essential hypertension, but the rs28933400 locus in the ATP1A2 gene may have no association with essential hypertension in the studied population.

    Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 2009;26;1;91-4

  • The structure of the Na+,K+-ATPase and mapping of isoform differences and disease-related mutations.

    Morth JP, Poulsen H, Toustrup-Jensen MS, Schack VR, Egebjerg J, Andersen JP, Vilsen B and Nissen P

    Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, University of Aarhus, Gustav Wieds Vej 10C, Aarhus C, Denmark.

    The Na+,K+-ATPase transforms the energy of ATP to the maintenance of steep electrochemical gradients for sodium and potassium across the plasma membrane. This activity is tissue specific, in particular due to variations in the expressions of the alpha subunit isoforms one through four. Several mutations in alpha2 and 3 have been identified that link the specific function of the Na+,K+-ATPase to the pathophysiology of neurological diseases such as rapid-onset dystonia parkinsonism and familial hemiplegic migraine type 2. We show a mapping of the isoform differences and the disease-related mutations on the recently determined crystal structure of the pig renal Na+,K+-ATPase and a structural comparison to Ca2+-ATPase. Furthermore, we present new experimental data that address the role of a stretch of three conserved arginines near the C-terminus of the alpha subunit (Arg1003-Arg1005).

    Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2009;364;1514;217-27

  • Diverse functional consequences of mutations in the Na+/K+-ATPase alpha2-subunit causing familial hemiplegic migraine type 2.

    Tavraz NN, Friedrich T, Dürr KL, Koenderink JB, Bamberg E, Freilinger T and Dichgans M

    Technical University of Berlin, Institute of Chemistry, D-10623 Berlin, Germany.

    Mutations in ATP1A2, the gene coding for the Na(+)/K(+)-ATPase alpha(2)-subunit, are associated with both familial hemiplegic migraine and sporadic cases of hemiplegic migraine. In this study, we examined the functional properties of 11 ATP1A2 mutations associated with familial or sporadic hemiplegic migraine, including missense mutations (T263M, T376M, R383H, A606T, R763H, M829R, R834Q, R937P, and X1021R), a deletion mutant (del(K935-S940)ins(I)), and a frameshift mutation (S966fs). According to the Na(+)/K(+)-ATPase crystal structure, a subset of the mutated residues (Ala(606), Arg(763), Met(829), and Arg(834)) is involved in important interdomain H-bond networks, and the C terminus of the enzyme, which is elongated by the X1021R mutation, has been implicated in voltage dependence and formation of a third Na(+)-binding site. Upon heterologous expression in Xenopus oocytes, the analysis of electrogenic transport properties, Rb(+) uptake, and protein expression revealed pronounced and markedly diverse functional alterations in all ATP1A2 mutants. Abnormalities included a complete loss of function (T376M), impaired plasma membrane expression (del(K935-S940)ins(I) and S966fs), and altered apparent affinities for extracellular cations or reduced enzyme turnover (R383H, A606T, R763H, R834Q, and X1021R). In addition, changes in the voltage dependence of pump currents and the increased rate constants of the voltage jump-induced redistribution between E(1)P and E(2)P states were observed. Thus, mutations that disrupt distinct interdomain H-bond patterns can cause abnormal conformational flexibility and exert long range consequences on apparent cation affinities or voltage dependence. Of interest, the X1021R mutation severely impaired voltage dependence and kinetics of Na(+)-translocating partial reactions, corroborating the critical role of the C terminus of Na(+)/K(+)-ATPase in these processes.

    The Journal of biological chemistry 2008;283;45;31097-106

  • 'Absence of T378N mutation of ATP1A2 gene in five patients with alternating hemiplegia of childhood'.

    Boileau S, Vuillaume I, Sablonnière B, Marignier S, Des Portes V, Vallée L and Auvin S

    Developmental medicine and child neurology 2008;50;11;879-80

  • A novel de novo nonsense mutation in ATP1A2 associated with sporadic hemiplegic migraine and epileptic seizures.

    Gallanti A, Tonelli A, Cardin V, Bussone G, Bresolin N and Bassi MT

    Dino Ferrari Center, IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena Foundation, Dept. of Neurological Sciences, University of Milan, 20129 Milan, Italy.

    Familial hemiplegic migraine (FHM) is a severe dominant form of migraine with aura associated with transient hemiparesis. Several other neurological signs and symptoms can be associated with FHM such as cerebellar abnormalities, cerebral edema and coma after minor head trauma, epileptic seizures and mental retardation. The sporadic form of hemiplegic migraine named SHM, presents with identical clinical symptoms. Here we report a case of a young hemiplegic migraine patient, 11 years old, who had the first hemiplegic attack at the age of 10 years. This patient has a clinical history of epileptic seizures in the childhood successfully controlled with drug therapy. No familiarity for any type of migraine or seizures can be observed within the paternal or maternal line. The patient who can therefore be considered a sporadic case, carries a novel de novo nonsense mutation p.Tyr1009X in the ATP1A2 gene (FHM2), leading to a truncated alpha-2 subunit of the Na+/K+-ATPase pump thus lacking the last 11 amino acids. The novel mutation identified confirms the role of FHM2 gene in forms of hemiplegic migraine associated with epilepsy with both familial and sporadic occurrence, and expands the spectrum of mutations related to these forms of the disease.

    Journal of the neurological sciences 2008;273;1-2;123-6

  • Screen for CACNA1A and ATP1A2 mutations in sporadic hemiplegic migraine patients.

    Thomsen LL, Oestergaard E, Bjornsson A, Stefansson H, Fasquel AC, Gulcher J, Stefansson K and Olesen J

    Danish Headache Centre, University of Copenhagen, Department of Neurology, Glostrup Hospital, Glostrup, Denmark. llt@dadlnet.dk

    The aim of this study was to investigate the involvement of the CACNA1A and ATP1A2 gene in a population-based sample of sporadic hemiplegic migraine (SHM). Patients with SHM (n = 105) were identified in a nationwide search in the Danish population. We sequenced all exons and promoter regions of the CACNA1A and ATP1A2 genes in 100 patients with SHM to search for possible SHM mutations. Novel DNA variants were discovered in eight SHM patients, four in exons of the CACNA1A gene and four in exons of the ATP1A2 gene. Six of the variants were considered non-pathogenic. The causal role of the two remaining DNA variants is unknown until functional studies have been made or independent genetic evidence is discovered. Only very few DNA variants were identified in 100 SHM patients, and regardless of whether the identified variants are causal the CACNA1A and ATP1A2 genes are not major genes in SHM.

    Cephalalgia : an international journal of headache 2008;28;9;914-21

  • Severe attacks of familial hemiplegic migraine, childhood epilepsy and ATP1A2 mutation.

    Lebas A, Guyant-Maréchal L, Hannequin D, Riant F, Tournier-Lasserve E and Parain D

    Departments of Paediatrics, Rouen University Hospital, Rouen, France. axel.lebas@gmail.com

    We studied four members of a family suffering from typical attacks of familial hemiplegic migraine (FHM) caused by a new mutation, R548C, of ATP1A2 gene in exon 12. One individual had also childhood absence epilepsy and generalized tonic-clonic seizures (GTCS). GTCS were followed by a severe attack of hemiplegic migraine at four times. Sodium valproate enabled control of both the epileptic seizures and the most severe FHM attacks. This association of FHM and epileptic seizures and their control with the same treatment suggest similar pathophysiological mechanisms.

    Cephalalgia : an international journal of headache 2008;28;7;774-7

  • Genetics of migraine: an update with special attention to genetic comorbidity.

    Stam AH, van den Maagdenberg AM, Haan J, Terwindt GM and Ferrari MD

    Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.

    To highlight recent genetic findings in migraine and discuss, new mutations in hemiplegic migraine genes in familial and sporadic cases and relevant candidate gene association studies. Special attention will be given to comorbid diseases of migraine.

    Familial hemiplegic migraine (FHM) is genetically heterogeneous with mutations in the CACNA1A (FHM1), ATP1A2 (FHM2) and SCN1A (FHM3) genes. Nineteen novel ATP1A2 mutations were identified last year, eleven of them in FHM2 families. A systematic genetic analysis of patients with sporadic hemiplegic migraine revealed five mutations in this gene, which has implications for genetic counselling. The identification of a second FHM3 SCN1A mutation definitely established SCN1A as a migraine gene. The identification of TREX1 mutations in families with retinal vasculopathy and associated diseases such as migraine may provide new insights in migraine pathophysiology.

    Summary: Many novel ATP1A2 mutations were identified in patients with familial and sporadic hemiplegic migraine. In sporadic patients, ATP1A2 screening has the highest chance of finding a causal mutation. A second FHM3 mutation definitely established the epilepsy SCN1A gene as a migraine gene. The discovery of genes in monogenic diseases in which migraine is prominent may lead to new insights in the molecular pathways involved in migraine pathophysiology.

    Current opinion in neurology 2008;21;3;288-93

  • ATP1A2 gene mutations are not present in two sisters with basilar-type migraine associated with menses.

    Cologno D, d'Onofrio F, Esposito T, Gianfrancesco F, Petretta V, Casucci G, Frediani F, Buzzi MG and Bussone G

    Institute of Clinical Neurophysiology Department of Neuroscience, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Foggia, Italy. danielacologno@virgilio.it

    Basilar-type migraine (BM) and hemiplegic migraine are clinically distinct subtypes of migraine with aura, however they do share clinical features and it is possible they may share genetic bases. In recent years, ATP1A2 and other gene mutations have been discovered in familial and sporadic hemiplegic migraine. More recently, an ATP1A2 mutation has been identified in an Italian family with BM. In this study we document the absence of ATP1A2 mutations in two Italian sisters with menstrual BM, suggesting that other genes are involved in the condition.

    Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology 2008;29;2;113-5

  • Familial hemiplegic migraine type 2 does not share hypersensitivity to nitric oxide with common types of migraine.

    Hansen JM, Thomsen LL, Marconi R, Casari G, Olesen J and Ashina M

    Danish Headache Centre and Department of Neurology, Glostrup Hospital, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. jamoha01@glo.regionh.dk

    Familial hemiplegic migraine type 2 (FHM-2) and common types of migraine show phenotypic similarities which may indicate a common neurobiological background. The nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a crucial role in migraine pathophysiology. Therefore, we tested the hypothesis that ATP1A2 mutations in patients with FHM-2 are associated with hypersensitivity to NO-cGMP pathway. Eight FHM-2 patients with R202Q, R763C, V138A and L764P mutations and nine healthy controls received intravenous infusions of 0.5 mug kg(-1) min(-1) glyceryl trinitrate (GTN) over 20 min. We recorded the following variables: headache intensity on a verbal rating scale; mean flow velocity in the middle cerebral artery (V(meanMCA)) by transcranial Doppler; diameter of the superficial temporal artery (STA) by ultrasound. The primary end-points were differences in incidence of migraine headache and area under the curve (AUC) for headache score during an immediate phase (0-120 min) and a delayed phase (2-14 h) after start of infusion. We found no difference in the incidence of reported migraine between FHM-2 patients, 25% (two out of eight), and controls, 0% (0 out of nine) (95% confidence interval -0.06, 0.56) (P = 0.21). The AUC(headache) in the immediate (P = 0.37) and delayed (P = 0.09) phase was not different between patients and controls. The GTN infusion resulted in a biphasic response in patients. During the immediate phase, the median peak headache occurred at 30 min and tended to be higher in patients, 1 (0, 3.8), than in controls, 0 (0, 1) (P = 0.056). During the delayed phase, the median peak headache occurred 4 h after the start of the infusion and was significantly higher in patients, 2.5 (0, 3), than in controls, 0 (0, 0) (P = 0.046). We found no difference in the AUC(VmeanMCA) (P = 0.77) or AUC(STA) (P = 0.53) between FHM-2 patients and controls. GTN infusion failed to induce more migraine in FHM-2 patients than in controls. The pathophysiological pathways underlying migraine headache in FHM-2 may be different from the common types of migraine.

    Cephalalgia : an international journal of headache 2008;28;4;367-75

  • Epilepsy as part of the phenotype associated with ATP1A2 mutations.

    Deprez L, Weckhuysen S, Peeters K, Deconinck T, Claeys KG, Claes LR, Suls A, Van Dyck T, Palmini A, Matthijs G, Van Paesschen W and De Jonghe P

    Neurogenetics Group, Department of Molecular Genetics, VIB; Antwerpen, Belgium.

    Purpose: Mutations in the ATP1A2 gene have been described in families with familial hemiplegic migraine (FHM). FHM is a variant of migraine with aura characterized by the occurrence of hemiplegia during the aura. Within several FHM families, some patients also had epileptic seizures. In this study we tested the hypothesis that mutations in ATP1A2 may be common in patients presenting with epilepsy and migraine.

    Methods: We selected 20 families with epilepsy and migraine and performed mutation analysis of ATP1A2 in the probands by direct sequencing of all exons and splice-site junctions.

    Results: Novel ATP1A2 mutations were found in two of the 20 families (10%). The p.Gly900Arg mutation was present in a family with epilepsy and FHM, and the p.Cys702Tyr mutation occurred in a family with occipitotemporal epilepsy and migraine with and without visual aura. In the two families together, six mutation carriers had the combination of epilepsy and migraine, two had only epilepsy, and six had only migraine.

    Discussion: This study shows that a history of migraine and a family history of both epilepsy and migraine should be obtained in all patients presenting with epilepsy in the epilepsy clinic. It may be worthwhile to screen patients with a combination of epilepsy and migraine and a positive family history of either migraine or epilepsy for mutations in the ATP1A2 gene.

    Epilepsia 2008;49;3;500-8

  • A novel ATP1A2 gene mutation in an Irish familial hemiplegic migraine kindred.

    Fernandez DM, Hand CK, Sweeney BJ and Parfrey NA

    Department of Neurology, Cork University Hospital, Wilton, Cork, Ireland.

    Objective: We studied a large Irish Caucasian pedigree with familial hemiplegic migraine (FHM) with the aim of finding the causative gene mutation.

    Background: FHM is a rare autosomal-dominant subtype of migraine with aura, which is linked to 4 loci on chromosomes 19p13, 1q23, 2q24, and 1q31. The mutations responsible for hemiplegic migraine have been described in the CACNA1A gene (chromosome 19p13), ATP1A2 gene (chromosome 1q23), and SCN1A gene (chromosome 2q24).

    Methods: We performed linkage analyses in this family for chromosome 1q23 and performed mutation analysis of the ATP1A2 gene.

    Results: Linkage to the FHM2 locus on chromosome 1 was demonstrated. Mutation screening of the ATP1A2 gene revealed a G to C substitution in exon 22 resulting in a novel protein variant, D999H, which co-segregates with FHM within this pedigree and is absent in 50 unaffected individuals. This residue is also highly conserved across species.

    Conclusions: We propose that D999H is a novel FHM ATP1A2 mutation.

    Headache 2008;48;1;101-8

  • Two novel functional mutations in the Na+,K+-ATPase alpha2-subunit ATP1A2 gene in patients with familial hemiplegic migraine and associated neurological phenotypes.

    Castro MJ, Nunes B, de Vries B, Lemos C, Vanmolkot KR, van den Heuvel JJ, Temudo T, Barros J, Sequeiros J, Frants RR, Koenderink JB, Pereira-Monteiro JM and van den Maagdenberg AM

    Instituto de Ciências Biomédicas Abel Salazar, and UnIGENe, Instituto Biologia Molecular Celular, Universidade do Porto, Porto, Portugal.

    Mutations in the ATP1A2 gene, encoding the alpha2-subunit of the Na+,K+-ATPase, are associated with familial hemiplegic migraine type 2. The majority of ATP1A2 mutations were reported in patients with hemiplegic migraine without any additional neurological findings. Here, we report on two novel ATP1A2 mutations that were identified in two Portuguese probands with hemiplegic migraine and interesting additional clinical features. The proband's of family 1 (with a V362E mutation) had mood alterations, classified as a borderline personality. The proband in family 2 (with a P796S mutation) had mild mental impairment, in addition to hemiplegic migraine; more severe mental retardation was observed in his brother, who also had hemiplegic migraine and carried the same mutation. Cell-survival assays clearly showed abnormal functioning of mutant Na+,K+-ATPase, indicating that both ATP1A2 mutants are disease causing. Additionally, our results suggest a possible causal relationship of the ATP1A2 mutations with the complex clinical phenotypes observed in the probands.

    Clinical genetics 2008;73;1;37-43

  • Purification of the human alpha2 Isoform of Na,K-ATPase expressed in Pichia pastoris. Stabilization by lipids and FXYD1.

    Lifshitz Y, Petrovich E, Haviv H, Goldshleger R, Tal DM, Garty H and Karlish SJ

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel.

    Human alpha1 and alpha2 isoforms of Na,K-ATPase have been expressed with porcine 10*Histidine-tagged beta1 subunit in Pichia pastoris. Methanol-induced expression of alpha2 is optimal at 20 degrees C, whereas at 25 degrees C, which is optimal for expression of alpha1, alpha2 is not expressed. Detergent-soluble alpha2beta1 and alpha1beta1 complexes have been purified in a stable and functional state. alpha2beta1 shows a somewhat lower Na,K-ATPase activity and higher K0.5K compared to alpha1beta1, while values of K0.5Na and KmATP are similar. Ouabain inhibits both alpha1beta1 (K0.5 24.6 +/- 6 nM) and alpha2beta1 (K0.5 102 +/- 14 nM) with high affinity. A striking difference between the isoforms is that alpha2beta1 is unstable. Both alpha1beta1 and alpha2beta1 complexes, prepared in C12E8 with an added phosphatidyl serine, are active, but alpha2beta1 is rapidly inactivated at 0 degrees C. Addition of low concentrations of cholesterol with 1-stearoyl-2-oleoyl-sn-glycero-3-[phospho-l-serine] (SOPS) stabilizes strongly, maintaining alpha2beta1 active up to two weeks at 0 degrees C. By contrast, alpha1beta1 is stable at 0 degrees C without added cholesterol. Both alpha1beta1 and alpha2beta1 complexes are stabilized by cholesterol at 37 degrees C. Human FXYD1 spontaneously associates in vitro with either alpha1beta1 or alpha2beta1, to form alpha1beta1/FXYD1 and alpha2beta1/FXYD1 complexes. The reconstituted FXYD1 18ee protects both alpha1beta1 and alpha2beta1 very strongly against thermal inactivation. Instability of alpha2 is attributable to suboptimal phophatidylserine-protein interactions. Residues within TM8, TM9 and TM10, near the alphabeta subunit interface, may play an important role in differential interactions of lipid with alpha1 and alpha2, and affect isoform stability. Possible physiological implications of isoform interactions with phospholipids and FXYD1 are discussed.

    Biochemistry 2007;46;51;14937-50

  • Systematic analysis of three FHM genes in 39 sporadic patients with hemiplegic migraine.

    de Vries B, Freilinger T, Vanmolkot KR, Koenderink JB, Stam AH, Terwindt GM, Babini E, van den Boogerd EH, van den Heuvel JJ, Frants RR, Haan J, Pusch M, van den Maagdenberg AM, Ferrari MD and Dichgans M

    Departments of Human Genetics, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.

    Background: Familial (FHM) and sporadic (SHM) hemiplegic migraine are severe subtypes of migraine associated with transient hemiparesis. For FHM, three genes have been identified encoding subunits of a calcium channel (CACNA1A), a sodium-potassium pump (ATP1A2), and a sodium channel (SCN1A). Their role in SHM is unknown. Establishing a genetic basis for SHM may further the understanding of its pathophysiology and relationship with common types of migraine. It will also facilitate the often difficult differential diagnosis from other causes of transient hemiparesis.

    Methods: We systematically scanned 39 well-characterized patients with SHM without associated neurologic features for mutations in the three FHM genes. Functional assays were performed for all new sequence variants.

    Results: Sequence variants were identified in seven SHM patients: one CACNA1A mutation, five ATP1A2 mutations, and one SCN1A polymorphism. All six mutations caused functional changes in cellular assays. One SHM patient later changed to FHM because another family member developed FHM attacks.

    Conclusion: We show that FHM genes are involved in at least a proportion of SHM patients without associated neurologic symptoms. Screening of ATP1A2 offers the highest likelihood of success. Because FHM gene mutations were also found in family members with "nonhemiplegic" typical migraine with and without aura, our findings reinforce the hypothesis that FHM, SHM, and "normal" migraine are part of a disease spectrum with shared pathogenetic mechanisms.

    Funded by: Telethon: GGP04018

    Neurology 2007;69;23;2170-6

  • Amino acid changes in the amino terminus of the Na,K-adenosine triphosphatase alpha-2 subunit associated to familial and sporadic hemiplegic migraine.

    Tonelli A, Gallanti A, Bersano A, Cardin V, Ballabio E, Airoldi G, Redaelli F, Candelise L, Bresolin N and Bassi MT

    IRCCS E. Medea, Laboratory of Molecular Biology, Bosisio Parini Lecco, Italy.

    Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura inherited with an autosomal dominant pattern. Here, we report the genetic analysis of four families and one sporadic case with hemiplegic migraine (HM) in whom we searched for mutations in the three genes associated with the disease CACNA1A, ATP1A2 and SCN1A. Two novel amino acid changes p.Arg65Trp and p.Tyr9Asn, in the Na,K-adenosine triphosphatase (ATPase) alpha-2 subunit encoded by the ATP1A2 gene, were found in one FHM family and in the sporadic case, respectively. These mutations are peculiar for their location in the extreme N-terminus, an uncommon mutation target in this protein. Low frequency of migraine attacks in all our mutant patients with low complexity of the associated aura symptoms in the sporadic case is also observed. Besides the two novel mutations, the data here reported confirm the involvement of ATP1A2 gene in the sporadic form of HM, while the negative results on the other families tested for all genes known in HM strengthen the hypothesis of the existence of at least another locus involved in FHM.

    Clinical genetics 2007;72;6;517-23

  • Association analysis of chromosome 1 migraine candidate genes.

    Fernandez F, Curtain RP, Colson NJ, Ovcaric M, MacMillan J and Griffiths LR

    Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia. f.fernandez@griffith.edu.au

    Background: Migraine with aura (MA) is a subtype of typical migraine. Migraine with aura (MA) also encompasses a rare severe subtype Familial Hemiplegic Migraine (FHM) with several known genetic loci. The type 2 FHM (FHM-2) susceptibility locus maps to chromosome 1q23 and mutations in the ATP1A2 gene at this site have recently been implicated. We have previously provided evidence of linkage of typical migraine (predominantly MA) to microsatellite markers on chromosome 1, in the 1q31 and 1q23 regions. In this study, we have undertaken a large genomic investigation involving candidate genes that lie within the chromosome 1q23 and 1q31 regions using an association analysis approach.

    Methods: We have genotyped a large population of case-controls (243 unrelated Caucasian migraineurs versus 243 controls) examining a set of 5 single nucleotide polymorphisms (SNPs) and the Fas Ligand dinucleotide repeat marker, located within the chromosome 1q23 and 1q31 regions.

    Results: Several genes have been studied including membrane protein (ATP 1 subtype A4 and FasL), cytoplasmic glycoprotein (CASQ 1) genes and potassium (KCN J9 and KCN J10) and calcium (CACNA1E) channel genes in 243 migraineurs (including 85% MA and 15% of migraine without aura (MO)) and 243 matched controls. After correction for multiple testing, chi-square results showed non-significant P values (P > 0.008) across all SNPs (and a CA repeat) tested in these different genes, however results with the KCN J10 marker gave interesting results (P = 0.02) that may be worth exploring further in other populations.

    Conclusion: These results do not show a significant role for the tested candidate gene variants and also do not support the hypothesis that a common chromosome 1 defective gene influences both FHM and the more common forms of migraine.

    BMC medical genetics 2007;8;57

  • First case of compound heterozygosity in Na,K-ATPase gene ATP1A2 in familial hemiplegic migraine.

    Vanmolkot KR, Stam AH, Raman A, Koenderink JB, de Vries B, van den Boogerd EH, van Vark J, van den Heuvel JJ, Bajaj N, Terwindt GM, Haan J, Frants RR, Ferrari MD and van den Maagdenberg AM

    Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands.

    Familial hemiplegic migraine (FHM) is a rare autosomal-dominant subtype of migraine with aura, associated with hemiparesis during the aura. Here we describe a unique FHM family in which two novel allelic missense mutations in the Na,K-ATPase gene ATP1A2 segregate in the proband with hemiplegic migraine. Both mutations show reduced penetrance in family members of the proband. Cellular survival assays revealed Na,K-ATPase dysfunction for both ATP1A2 mutants, indicating that both mutations are disease causative. This is the first case of compound heterozygosity for any of the known FHM genes.

    European journal of human genetics : EJHG 2007;15;8;884-8

  • Muscle Na+-K+-ATPase activity and isoform adaptations to intense interval exercise and training in well-trained athletes.

    Aughey RJ, Murphy KT, Clark SA, Garnham AP, Snow RJ, Cameron-Smith D, Hawley JA and McKenna MJ

    Muscle, Ions and Exercise Group, Centre for Ageing, Rehabilitation, Exercise and Sport, School of Human Movement, Recreation and Performance, Victoria University, Melbourne, Australia.

    The Na+ -K+ -ATPase enzyme is vital in skeletal muscle function. We investigated the effects of acute high-intensity interval exercise, before and following high-intensity training (HIT), on muscle Na+ -K+ -ATPase maximal activity, content, and isoform mRNA expression and protein abundance. Twelve endurance-trained athletes were tested at baseline, pretrain, and after 3 wk of HIT (posttrain), which comprised seven sessions of 8 x 5-min interval cycling at 80% peak power output. Vastus lateralis muscle was biopsied at rest (baseline) and both at rest and immediately postexercise during the first (pretrain) and seventh (posttrain) training sessions. Muscle was analyzed for Na+ -K+ -ATPase maximal activity (3-O-MFPase), content ([3H]ouabain binding), isoform mRNA expression (RT-PCR), and protein abundance (Western blotting). All baseline-to-pretrain measures were stable. Pretrain, acute exercise decreased 3-O-MFPase activity [12.7% (SD 5.1), P < 0.05], increased alpha1, alpha2, and alpha3 mRNA expression (1.4-, 2.8-, and 3.4-fold, respectively, P < 0.05) with unchanged beta-isoform mRNA or protein abundance of any isoform. In resting muscle, HIT increased (P < 0.05) 3-O-MFPase activity by 5.5% (SD 2.9), and alpha3 and beta3 mRNA expression by 3.0- and 0.5-fold, respectively, with unchanged Na+ -K+ -ATPase content or isoform protein abundance. Posttrain, the acute exercise induced decline in 3-O-MFPase activity and increase in alpha1 and alpha3 mRNA each persisted (P < 0.05); the postexercise 3-O-MFPase activity was also higher after HIT (P < 0.05). Thus HIT augmented Na+ -K+ -ATPase maximal activity despite unchanged total content and isoform protein abundance. Elevated Na+ -K+ -ATPase activity postexercise may contribute to reduced fatigue after training. The Na+ -K+ -ATPase mRNA response to interval exercise of increased alpha- but not beta-mRNA was largely preserved posttrain, suggesting a functional role of alpha mRNA upregulation.

    Journal of applied physiology (Bethesda, Md. : 1985) 2007;103;1;39-47

  • Recurrent ATP1A2 mutations in Portuguese families with familial hemiplegic migraine.

    Castro MJ, Stam AH, Lemos C, Barros J, Gouveia RG, Martins IP, Koenderink JB, Vanmolkot KR, Mendes AP, Frants RR, Ferrari MD, Sequeiros J, Pereira-Monteiro JM and van den Maagdenberg AM

    Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.

    Familial hemiplegic migraine is a rare autosomal dominant subtype of migraine with aura. Three genes have been identified, all involved in ion transport. There is considerable clinical variation associated with FHM mutations. Genotype-phenotype correlation studies are needed, but are challenging mainly because the number of carriers of individual mutations is low. One exception is the recurrent T666M mutation in the FHM1 CACNA1A gene that was identified in almost one-third of FHM families and showed variable associated clinical features and severity, both within and among FHM families. Similar studies in the FHM2 ATP1A2 gene have not been performed because of the low number of carriers with individual mutations. Here we report on the recurrence of ATP1A2 mutations M731T and T376M that affect sodium-potassium pump functioning in two Portuguese FHM families. Considerably increasing the number of mutation carriers with these mutations indicated a clear genotype-phenotype correlation: both mutations are associated with pure FHM. In addition, we show that recurrent mutations for ATP1A2 are more frequent than previously thought, which has implications for genotype-phenotype correlations and genetic testing.

    Journal of human genetics 2007;52;12;990-8

  • Mutation analysis of CACNA1A and ATP1A2 genes in Brazilian FHM families.

    Lopes LR, Peres MF, Vanmolkot KR, Tobo PR, Zukerman E, Frants RR, van den Maagdenberg AM and Moreira-Filho CA

    Instituto de Ensino e Pesquisa, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil, and Leiden University Medical Center, The Netherlands. lucianarl@einstein.br

    Familial hemiplegic migraine (FHM) is a rare autosomal dominant form of migraine with aura. This disease has been associated with missense mutations in the CACNA1A and ATP1A2 genes. The aim of this study was to identify whether CACNA1A and ATP1A2 are or not related to Brazilian FHM. Here we screened four Brazilian FHM families (total of 26 individuals--13 affected and 13 asymptomatic or normal) for mutations in both genes. We found an amino acid change in a member of family FHM-D (Arg2206Gly). However since this alteration is not present in all affected individuals and is present in one asymptomatic individual it should be considered a polymorphism. Further studies with additional families will be necessary to reveal the importance of both CACNA1A and ATP1A2 genes on the pathogeneses of FHM in Brazil and to test the third gene (SCN1A) in these FHM families.

    Arquivos de neuro-psiquiatria 2006;64;3A;549-52

  • Two de novo mutations in the Na,K-ATPase gene ATP1A2 associated with pure familial hemiplegic migraine.

    Vanmolkot KR, Kors EE, Turk U, Turkdogan D, Keyser A, Broos LA, Kia SK, van den Heuvel JJ, Black DF, Haan J, Frants RR, Barone V, Ferrari MD, Casari G, Koenderink JB and van den Maagdenberg AM

    Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands, and Department of Neurology, Dr Lütfi Kirdar State Hospital, Maltepe, Istanbul, Turkey.

    Familial hemiplegic migraine (FHM) is a rare autosomal dominantly inherited subtype of migraine, in which hemiparesis occurs during the aura. The majority of the families carry mutations in the CACNA1A gene on chromosome 19p13 (FHM1). About 20% of FHM families is linked to chromosome 1q23 (FHM2), and has mutations in the ATP1A2 gene, encoding the alpha2-subunit of the Na,K-ATPase. Mutation analysis in a Dutch and a Turkish family with pure FHM revealed two novel de novo missense mutations, R593W and V628M, respectively. Cellular survival assays support the hypothesis that both mutations are disease-causative. The identification of the first de novo mutations underscores beyond any doubt the involvement of the ATP1A2 gene in FHM2.

    European journal of human genetics : EJHG 2006;14;5;555-60

  • The CACNA1A and ATP1A2 genes are not involved in dominantly inherited migraine with aura.

    Kirchmann M, Thomsen LL and Olesen J

    Department of Neurology, Danish Headache Center, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark. kirchmann@dadlnet.dk

    Epidemiological studies indicate that migraine with typical aura (MA) has a major genetic component but the genes for MA have not been identified. However, the autosomal dominantly inherited familial hemiplegic migraine (FHM) is often caused by mutations in the CACNA1A or ATP1A2 genes. The aim of the study was to investigate if the CACNA1A or ATP1A2 genes are involved in MA with an apparently autosomal dominant mode of inheritance. From a clinic population diagnosed by a trained physician we recruited 34 extended families (comprising 174 MA patients) with an apparently autosomal dominant mode of inheritance of MA. We performed a linkage analysis of 161 of 174 MA patients and 79 unaffected relatives using a framework marker set of 44 markers for chromosome 1 and 22 markers for chromosome 19. Linkage analysis was made with a non-parametric or autosomal dominant parametric model, either allowing for heterogeneity or not, using an affected only analysis. We identified no linkage to CACNA1A and ATP1A2 loci on chromosome 19 or 1, respectively. Additionally, at least two patients from each family and 92 healthy, unrelated controls were selected for a sequence analysis. We sequenced the 48 exons of CACNA1A and the 23 exons of ATP1A2, including promoter and flanking intron sequences. No polymorphism was identified in the CACNA1A or ATP1A2 genes with a strong correlation to MA. Our study shows that the CACNA1A or ATP1A2 genes are probably not involved in MA. To identify the genes involved in the common forms of migraine, future genetic studies should focus on MA and migraine without aura (MO) and not FHM.

    American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 2006;141B;3;250-6

  • Haplotype-based systematic association studies of ATP1A2 in migraine with aura.

    Netzer C, Todt U, Heinze A, Freudenberg J, Zumbroich V, Becker T, Goebel I, Ohlraun S, Goebel H and Kubisch C

    Institute of Human Genetics, University of Cologne, Cologne, Germany.

    Mutations in ATP1A2 cause familial hemiplegic migraine (FHM) type 2, a rare monogenic form of migraine with aura (MA). Moreover, rare ATP1A2 missense variants are found in familial clustering of common forms of migraine in single pedigrees. To determine whether also common ATP1A2 polymorphisms contribute to MA pathogenesis, we performed systematic case-control association studies in 284 MA cases and 241 control individuals. By direct sequencing of the 23 coding exons and adjacent intronic regions in 45 MA patients, 16 polymorphisms (12 SNPs, 3 small indels, 1 microsatellite marker) were identified. The sequencing results were used to estimate seven common ATP1A2 haplotypes (with a frequency >5%) covering about 97% of total haplotype diversity for this region. Subsequently, six haplotype-tagging SNPs/polymorphisms were genotyped in 95 individuals with a family history of MA, in 189 individuals with sporadic MA, and in a gender-matched control sample. A haplotype analysis was performed using the program FAMHAP. No significant differences in the ATP1A2 haplotype distribution could be detected between MA patients (or patient subgroups) and the control group. In a single-marker analysis the allele and genotype frequencies of ATP1A2 polymorphisms between cases and controls were compared. Neither the six ht-SNPs nor a single allele of the microsatellite marker were significantly associated with MA. In summary, we found no evidence for a common contribution of ATP1A2 to the pathogenesis of complex inherited MA.

    American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 2006;141B;3;257-60

  • Severe episodic neurological deficits and permanent mental retardation in a child with a novel FHM2 ATP1A2 mutation.

    Vanmolkot KR, Stroink H, Koenderink JB, Kors EE, van den Heuvel JJ, van den Boogerd EH, Stam AH, Haan J, De Vries BB, Terwindt GM, Frants RR, Ferrari MD and van den Maagdenberg AM

    Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands.

    Objective: Attacks of familial hemiplegic migraine (FHM) are usually associated with transient, completely reversible symptoms. Here, we studied the ATP1A2 FHM2 gene in a young girl with episodes of both very severe and transient neurological symptoms that were triggered by mild head trauma as well as permanent mental retardation. Her family members suffered from hemiplegic and confusional migraine attacks.

    Methods: Mutation analysis of the ATP1A2 gene was performed by direct sequencing of all exons and flanking intronic regions, using genomic DNA of the proband. Functional consequences of the mutation were analyzed by cellular survival assays.

    Results: We identified a novel G615R ATP1A2 mutation in the proband and several of her family members. Functional analysis of mutant Na,K-ATPase in cellular survival assays showed a complete loss-of-function effect.

    Interpretation: Permanent mental retardation in children may be caused by ATP1A2 mutations.

    Annals of neurology 2006;59;2;310-4

  • Thyrotoxic periodic paralysis and polymorphisms of sodium-potassium ATPase genes.

    Kung AW, Lau KS, Cheung WM and Chan V

    Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China. awckung@hkucc.hku.hk

    Objective: Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism association with recurrent, reversible episodes of muscle weakness. Increased sodium-potassium ATPase (Na/K-ATPase) pump activity is postulated to contribute to the hypokalaemic paralytic attacks in TPP. The aim of this study was to determine the genetic predisposition to TPP in relation to Na/K-ATPase genes.

    Design: A case-control association study.

    Patients: Ninety-nine male Chinese TPP patients were compared to 84 male Graves' disease (GD) patients without TPP and 100 normal male controls.

    Measurement: A total of 1500 base pairs upstream of the transcriptional start site of the five Na/K-ATPase genes that are expressed in the skeletal muscles, namely ATP1A1, ATP1A2, ATP1B1, ATP1B2 and ATP1B4, were sequenced in all subjects for mutations or polymorphisms. The single nucleotide polymorphisms (SNPs) of the coding regions of the five genes were also studied for association with TPP.

    Results: No mutations were detected in the 5' regions of the five genes in any of the patients studied. There was no difference in the distribution of SNPs and SNP haplotypes in the upstream and coding region of these genes between the three groups of subjects.

    Conclusion: No association between the polymorphisms of ATP1A1, ATP1A2, ATP1B1, ATP1B2 and ATP1B4 genes and TPP could be detected.

    Clinical endocrinology 2006;64;2;158-61

  • Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes.

    Kimura K, Wakamatsu A, Suzuki Y, Ota T, Nishikawa T, Yamashita R, Yamamoto J, Sekine M, Tsuritani K, Wakaguri H, Ishii S, Sugiyama T, Saito K, Isono Y, Irie R, Kushida N, Yoneyama T, Otsuka R, Kanda K, Yokoi T, Kondo H, Wagatsuma M, Murakawa K, Ishida S, Ishibashi T, Takahashi-Fujii A, Tanase T, Nagai K, Kikuchi H, Nakai K, Isogai T and Sugano S

    Life Science Research Laboratory, Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, 185-8601, Japan.

    By analyzing 1,780,295 5'-end sequences of human full-length cDNAs derived from 164 kinds of oligo-cap cDNA libraries, we identified 269,774 independent positions of transcriptional start sites (TSSs) for 14,628 human RefSeq genes. These TSSs were clustered into 30,964 clusters that were separated from each other by more than 500 bp and thus are very likely to constitute mutually distinct alternative promoters. To our surprise, at least 7674 (52%) human RefSeq genes were subject to regulation by putative alternative promoters (PAPs). On average, there were 3.1 PAPs per gene, with the composition of one CpG-island-containing promoter per 2.6 CpG-less promoters. In 17% of the PAP-containing loci, tissue-specific use of the PAPs was observed. The richest tissue sources of the tissue-specific PAPs were testis and brain. It was also intriguing that the PAP-containing promoters were enriched in the genes encoding signal transduction-related proteins and were rarer in the genes encoding extracellular proteins, possibly reflecting the varied functional requirement for and the restricted expression of those categories of genes, respectively. The patterns of the first exons were highly diverse as well. On average, there were 7.7 different splicing types of first exons per locus partly produced by the PAPs, suggesting that a wide variety of transcripts can be achieved by this mechanism. Our findings suggest that use of alternate promoters and consequent alternative use of first exons should play a pivotal role in generating the complexity required for the highly elaborated molecular systems in humans.

    Genome research 2006;16;1;55-65

  • Familial basilar migraine associated with a new mutation in the ATP1A2 gene.

    Ambrosini A, D'Onofrio M, Grieco GS, Di Mambro A, Montagna G, Fortini D, Nicoletti F, Nappi G, Sances G, Schoenen J, Buzzi MG, Santorelli FM and Pierelli F

    Headache Clinic, INM Neuromed, Pozzilli, Italy. anna.ambrosini@neuromed.it

    Basilar migraine (BM), familial hemiplegic migraine (FHM), and sporadic hemiplegic migraine (SHM) are phenotypically similar subtypes of migraine with aura, differentiated only by motor symptoms, which are absent in BM. Mutations in CACNA1A and ATP1A2 have been found in FHM. The authors detected a novel mutation in the ATP1A2 gene (R548H) in members of a family with BM, suggesting that BM and FHM may be allelic disorders.

    Neurology 2005;65;11;1826-8

  • No evidence of ATP1A2 involvement in 12 multiplex Italian families with benign familial infantile seizures.

    Martinelli Boneschi F, Aridon P, Zara F, Guerrini R, Marini C, De Fusco M, Comi G and Casari G

    Department of Neurology, San Raffaele Scientific Institute, 20131 Milan, Italy. filippo.martinelli@hsr.it

    A missense mutation in the gene encoding the alpha(2) subunit of the Na(+),K(+) ATPase pump (ATP1A2) was found in a family with both familial hemiplegic migraine (FHM) and Benign Familial Infantile Seizures (BFIC). As it is still unclear whether ATP1A2 is responsible for pure BFIC syndromes, we checked mutations of the ATP1A2 gene in probands of 12 Italian multiplex families with pure BFIC, who were negative for mutations in the SCN2A gene. We screened the ATP1A2 gene by denaturing high performance liquid chromatography (D-HPLC) and direct sequencing of DNA fragments showing an aberrant elution pattern. We found one exonic variant and five intronic variants, none leading to significant amino acid changes or causing a modification of the physiological mRNA maturation. The ATP1A2 gene does not appear to be involved in the ethiopathogenesis of pure BFIC syndromes, at least in the explored Italian multiplex families. It could be either responsible of a minority of cases, or of complex syndromes where BFIC and FHM co-occur.

    Neuroscience letters 2005;388;2;71-4

  • Rare missense variants in ATP1A2 in families with clustering of common forms of migraine.

    Todt U, Dichgans M, Jurkat-Rott K, Heinze A, Zifarelli G, Koenderink JB, Goebel I, Zumbroich V, Stiller A, Ramirez A, Friedrich T, Göbel H and Kubisch C

    Institut für Humangenetik, Universitätsklinikum Bonn, Bonn, Germany.

    Migraine is a recurrent neurovascular disease. Its two most common forms-migraine without aura (MO) and migraine with aura (MA)-both show familial clustering and a complex pattern of inheritance. Familial hemiplegic migraine (FHM) is a rare monogenic subform caused by mutations in the calcium channel gene CACNA1A or the Na(+)/K(+)-ATPase gene ATP1A2. An involvement of FHM genes in the pathogenesis of common forms of migraine is not proven. We therefore systematically screened ATP1A2 in families with several members affected by MA and/or MO. We identified two novel missense alterations [c.520G>A (p.E174 K) and c.1544G>A (p.C515Y)] in two out of 45 families, which were not found in 520 control chromosomes. Functional studies of these variants in Xenopus oocytes by two-electrode voltage clamp measurements and radiochemical determination of ATPase activity showed that C515Y leads to a complete loss of function comparable with the effect of FHM-mutations whereas for E174 K no functional alteration could be found in the in vitro assays. In conclusion we propose that rare variants in ATP1A2 are involved in the susceptibility to common forms of migraine, because of 1) the absence of alterations in controls, 2) the particular pattern of segregation in both families, 3) the high conservation of mutated residues in Na(+)/K(+)-ATPases, 4) the functional effect of C515Y, and 5) the involvement of ATP1A2 in a monogenic form of migraine.

    Human mutation 2005;26;4;315-21

  • ATP1A2 mutations in 11 families with familial hemiplegic migraine.

    Riant F, De Fusco M, Aridon P, Ducros A, Ploton C, Marchelli F, Maciazek J, Bousser MG, Casari G and Tournier-Lasserve E

    Laboratoire de Génétique Moléculaire, Hôpital Lariboisière AP-HP, Paris, France.

    Familial hemiplegic migraine (FHM) is an autosomal dominant form of migraine with aura. The disease is caused by mutations of at least three genes among which two have been identified, CACNA1A and ATP1A2. Very few mutations have been identified so far in ATP1A2. We screened the coding sequence of ATP1A2 in 26 unrelated FHM probands in whom CACNA1A screening was negative. A total of eight different mutations were identified in 11 of the probands (41%), including six missense mutations, one small deletion leading to a frameshift, and one in frame deletion. All were novel mutations. Two mutations were recurrent, in three and two families, respectively. Genotyping of 94 relatives of these 11 probands identified 47 mutation carriers, among whom 36 were clinically affected. Sequencing of all 23 exons in an ethnically matched panel detected only one exonic coding polymorphism.

    Human mutation 2005;26;3;281

  • Alterations in the alpha2 isoform of Na,K-ATPase associated with familial hemiplegic migraine type 2.

    Segall L, Mezzetti A, Scanzano R, Gargus JJ, Purisima E and Blostein R

    Departments of Biochemistry and Medicine, McGill University and Montreal General Hospital Research Institute, Montreal, Quebec, Canada H3G 1A4.

    A number of missense mutations in the Na,K-ATPase alpha2 catalytic subunit have been identified in familial hemiplegic migraine with aura. Two alleles (L764P and W887R) showed loss-of-function, whereas a third (T345A) is fully functional but with altered Na,K-ATPase kinetics. This study describes two additional mutants, R689Q and M731T, originally identified by Vanmolkot et al. [Vanmolkot, K. R., et al. (2003) Ann. Neurol. 54, 360-366], which we show here to also be functional and kinetically altered. Both mutants have reduced catalytic turnover and increased apparent affinity for extracellular K(+). For both R689Q and M731T, sensitivity to vanadate inhibition is decreased, suggesting that the steady-state E(1) <==> E(2) poise of the enzyme is shifted toward E(1). Whereas the K'(ATP) is not affected by the R689Q replacement, the M731T mutant has an increase in apparent affinity for ATP. Analysis of the structural changes effected by T345A, R689Q, and M731T mutations, based on homologous replacements in the known crystal structure of the sarcoplasmic reticulum Ca-ATPase, provides insights into the molecular bases for the kinetic alterations. It is suggested that the disease phenotype is the consequence of lowered molecular activity of the alpha2 pump isoform due to either decreased K(+) affinity (T345A) or catalytic turnover (R689Q and M731T), thus causing a delay in extracellular K(+) clearance and/or altered localized Ca(2+) handling/signaling secondary to reduced activity in colocalized Na(+)/Ca(2+) exchange.

    Proceedings of the National Academy of Sciences of the United States of America 2005;102;31;11106-11

  • No association between common variations in the human alpha 2 subunit gene (ATP1A2) of the sodium-potassium-transporting ATPase and idiopathic generalized epilepsy.

    Lohoff FW, Ferraro TN, Sander T, Zhao H, Dahl JP, Berrettini WH and Buono RJ

    Department of Psychiatry, University of Pennsylvania School of Medicine, Center for Neurobiology and Behavior, 3535 Market Street, 2nd Floor, R2070, Philadelphia, PA 19104, USA. lohoff@mail.med.upenn.edu

    Quantitative trait loci studies in inbred mice have identified a locus on chromosome 1 (Szs1) of fundamental importance to seizure susceptibility. High-ranking candidate genes in this susceptibility region include KCNJ9, KCNJ10 and ATP1A2. We performed a systematic mutation scan of the coding region of the human ATP1A2 gene and performed a case-control association study with seven common markers. Genotypes were assessed in 152 idiopathic generalized epilepsy (IGE) patients of German ancestry and 111 healthy German controls for all seven polymorphisms. No significant differences were found in genotype or allele frequencies for any of the variations between the IGE patients and controls. No haplotypes were associated with IGE when compared to controls. Linkage disequilibrium was demonstrated throughout the gene. Results suggest that the polymorphisms we studied in the ATP1A2 gene do not represent major susceptibility factors for common forms of IGE.

    Funded by: NIMH NIH HHS: R25 MH060490; NINDS NIH HHS: R01 NS40396

    Neuroscience letters 2005;382;1-2;33-8

  • A carboxy-terminus motif of HKalpha2 is necessary for assembly and function.

    Codina J, Li J and Dubose

    Sections of Nephrology and Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.

    Background: The present experiments were designed to study the importance of the carboxy-terminus of HKalpha2, for both function and integrity of assembly with beta1-Na+,K+-ATPase.

    Methods: For this purpose, stop codons were created, by polymerase chain reaction (PCR), at different positions in the carboxy-terminus of HKalpha2. Subsequently, chimeras between HKalpha2 and the carboxy-terminus of alpha1-Na+,K+-ATPase or with the carboxy-terminus of the gastric H+,K+-ATPase were created. Human embryonic kidney HEK-293 cells were used as expression systems for functional studies using 86Rb+ uptake and alpha/beta assembly using specific antibodies.

    Results: The results demonstrate that the entire carboxy-terminus of HKalpha2 is required for optimal protection of the alpha/beta complex from degradation and for functionality as evidenced by 86Rb+ uptake. The results also demonstrate that there was flexibility in the sequence of the carboxy-terminus. The last two tyrosines (Y1035Y1036) of HKalpha2 could be mutated to alanines and the carboxy-terminus of HKalpha2 could be replaced by the carboxy-terminus of alpha1-Na+,K+-ATPase while preserving transport activity.

    Conclusion: The entire carboxy-terminus of HKalpha2 is required for stable assembly with beta1-Na+,K+-ATPase and functionality.

    Funded by: NIDDK NIH HHS: DK-30603

    Kidney international 2004;66;6;2283-92

  • Translationally controlled tumor protein interacts with the third cytoplasmic domain of Na,K-ATPase alpha subunit and inhibits the pump activity in HeLa cells.

    Jung J, Kim M, Kim MJ, Kim J, Moon J, Lim JS, Kim M and Lee K

    College of Pharmacy, Center for Cell Signaling Research and Division of Molecular Life Sciences, Ewha Woman's University, Seoul 120-750, Korea.

    Translationally controlled tumor protein (TCTP) is a growth-related protein under transcriptional as well as translational control. We screened a rat skeletal muscle cDNA library using yeast two-hybrid system and found that TCTP interacts with the third large cytoplasmic domain of alpha1 as well as alpha2 isoforms of Na,K-ATPase, believed involved in the regulation of Na,K-ATPase activity. Interaction between TCTP and Na,K-ATPase was confirmed by coimmunoprecipitation in yeast and mammalian cells. We also showed, using (86)Rb(+) uptake assay, that overexpression of TCTP inhibited Na,K-ATPase activity in HeLa cells. Northern and Western blotting studies of HeLa cells transiently transfected with GFP-tagged TCTP showed that overexpression of TCTP did not change mRNA and protein levels of Na,K-ATPase. Recombinant TCTP protein purified from an Escherichia coli expression system inhibited purified HeLa cell plasma membrane Na,K-ATPase in a dose-dependent manner. Using deletion analysis, we also found that the C-terminal 102-172-amino-acid region of rat TCTP that contains the TCTP homology region 2 is essential for its association with, and inhibition of, Na,K-ATPase.

    The Journal of biological chemistry 2004;279;48;49868-75

  • Kinetic alterations due to a missense mutation in the Na,K-ATPase alpha2 subunit cause familial hemiplegic migraine type 2.

    Segall L, Scanzano R, Kaunisto MA, Wessman M, Palotie A, Gargus JJ and Blostein R

    Department of Biochemistry, McGill University, Montreal, Quebec H3G 1A4, Canada.

    A number of missense mutations in the ATP1A2 gene, which encodes the Na,K-ATPase alpha2 subunit, have been identified in familial hemiplegic migraine with aura. Loss of function and haploinsufficiency have been the suggested mechanisms in mutants for which functional analysis has been reported. This paper describes a kinetic analysis of mutant T345A, recently identified in a detailed genetic analysis of a large Finnish family (Kaunisto, M. A., Harno, H., Vanmolkot, K. R., Gargus, J. J., Sun, G., Hamalainen, E., Liukkonen, E., Kallela, M., van den Maagdenberg, A. M., Frants, R. R., Farkkila, M., Palotie, A., and Wessman, M. (2004) Neurogenetics 5, 141-146). Introducing T345A into the conserved rat alpha2 enzyme does not alter cell growth or catalytic turnover but causes a substantial decrease in apparent K+ affinity (2-fold increase in K0.5(K+)). In view of the location of Thr-345 in the cytoplasmic stalk domain adjacent to transmembrane segment 4, the 2-fold increase in K0.5(K+) is probably due to T345A replacement altering K+ occlusion/deocclusion. Faster K+ deocclusion of the mutant via the E2(K) + ATP --> E1.ATP + K+ partial reaction is evidenced in (i) a marked increase (300%) in K+ stimulation of Na-ATPase at micromolar ATP, (ii) a 4-fold decrease in KATP, and (iii) only a modest increase (approximately 3-fold) in I50 for vanadate, which was used as a probe of the steady state E1/E2 conformational equilibrium. We suggest that the decreased apparent K+ affinity is the basis for a reduced rate of extracellular K+ removal, which delays the recovery phase of nerve impulse transmission in the central nervous system and, thereby, the clinical picture of migraine with aura. This is the first demonstration of a mutation that leads to a disease associated with a kinetically altered but fully functional Na,K-ATPase, refining the molecular mechanism of pathogenesis in familial hemiplegic migraine.

    Funded by: NIMH NIH HHS: MH59222; NINDS NIH HHS: NS37675-02

    The Journal of biological chemistry 2004;279;42;43692-6

  • The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

    Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MS, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YS, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Morrin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJ, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J and MGC Project Team

    The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.

    Funded by: PHS HHS: N01-C0-12400

    Genome research 2004;14;10B;2121-7

  • A G301R Na+/K+ -ATPase mutation causes familial hemiplegic migraine type 2 with cerebellar signs.

    Spadaro M, Ursu S, Lehmann-Horn F, Veneziano L, Liana V, Antonini G, Giovanni A, Giunti P, Paola G, Frontali M and Jurkat-Rott K

    Department of Neurological Sciences, 1st Medical School, La Sapienza University, Rome, Italy.

    Familial hemiplegic migraine (FHM) is an autosomal dominant subtype of migraine with hemiparesis during the aura. In over 50% of cases the causative gene is CACNA1A (FHM1), which in some cases produces a phenotype with cerebellar signs, including ataxia and nystagmus. Recently, mutations in ATP1A2 on chromosome 1q23 encoding a Na+/K+ -ATPase subunit were identified in four families (FHM2). We now describe an FHM2 pedigree with a fifth ATP1A2 mutation coding for a G301R substitution. The phenotype was particularly severe and included hemiplegic migraine, seizure, prolonged coma, elevated temperature, sensory deficit, and transient or permanent cerebellar signs, such as ataxia, nystagmus, and dysarthria. A mild crossed cerebellar diaschisis during an attack further supported the clinical evidence of a cerebellar deficit. This is the first report suggesting cerebellar involvement in FHM2. A possible role for CACNA1A in producing the phenotype in this family was excluded by linkage studies to the FHM1 locus. The study of this family suggests that the absence of cerebellar signs may not be a reliable indicator to clinically differentiate FHM2 from FHM1.

    Neurogenetics 2004;5;3;177-85

  • A novel mutation in the ATP1A2 gene causes alternating hemiplegia of childhood.

    Bassi MT, Bresolin N, Tonelli A, Nazos K, Crippa F, Baschirotto C, Zucca C, Bersano A, Dolcetta D, Boneschi FM, Barone V and Casari G

    Journal of medical genetics 2004;41;8;621-8

  • A novel missense ATP1A2 mutation in a Finnish family with familial hemiplegic migraine type 2.

    Kaunisto MA, Harno H, Vanmolkot KR, Gargus JJ, Sun G, Hämäläinen E, Liukkonen E, Kallela M, van den Maagdenberg AM, Frants RR, Färkkilä M, Palotie A and Wessman M

    Biomedicum Helsinki, Research Program in Molecular Medicine, University of Helsinki, Helsinki, Finland. mari.kaunisto@hus.fi

    Familial hemiplegic migraine (FHM), a rare autosomal dominant subtype of migraine with aura, has been linked to two chromosomal loci, 19p13 and 1q23. Mutations in the Na+K+-ATPase alpha2 subunit gene, ATP1A2, on 1q23 have recently been shown to cause familial hemiplegic migraine type 2 (FHM2). We sequenced the coding regions of this gene in a Finnish chromosome 1q23-linked FHM family with associated symptoms such as coma and identified a novel A1033G mutation in exon 9. This mutation results in a threonine-to-alanine substitution at codon 345. This residue is located in a highly conserved N-terminal region of the M4-5 loop of the Na+,K+-ATPase. Furthermore, the T345A mutation co-segregated with the disorder in our family and was not present in 132 healthy Finnish control individuals. For these reasons it is most likely the FHM-causing mutation in this family.

    Funded by: NIMH NIH HHS: R01 MH59222; NINDS NIH HHS: R01 NS37675-02

    Neurogenetics 2004;5;2;141-6

  • Alternating hemiplegia of childhood or familial hemiplegic migraine? A novel ATP1A2 mutation.

    Swoboda KJ, Kanavakis E, Xaidara A, Johnson JE, Leppert MF, Schlesinger-Massart MB, Ptacek LJ, Silver K and Youroukos S

    Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA. Swoboda@genetics.utah.edu

    Alternating hemiplegia of childhood (AHC) is typically distinguished from familial hemiplegic migraine (FHM) by infantile onset of the characteristic symptoms and high prevalence of associated neurological deficits that become increasingly obvious with age. Expansion of the clinical spectrum in FHM recently has begun to blur the distinction between these disorders. We report a novel ATP1A2 mutation in a kindred with features that bridge the phenotypic spectrum between AHC and FHM syndromes, supporting a possible common pathogenesis in a subset of such cases. Mutation analysis in classic sporadic AHC patients and in an additional five kindreds in which linkage to the ATP1A2 locus could not be excluded failed to identify additional mutations.

    Funded by: NCRR NIH HHS: M01-RR00864

    Annals of neurology 2004;55;6;884-7

  • In vivo expression profile of a H+-K+-ATPase alpha2-subunit promoter-reporter transgene.

    Zhang W, Xia X, Zou L, Xu X, LeSage GD and Kone BC

    Depts. of Internal Medicine, The Univ. of Texas Medical School at Houston, 6431 Fannin, MSB 4.148, Houston, TX 77030, USA.

    Because little is known about the molecular basis of transcriptional regulation of the murine H(+)-K(+)-ATPase alpha(2) (HKalpha(2)) gene or other genes whose expression is restricted in part to the collecting duct, especially in vivo, we developed transgenic mice carrying an insertional HKalpha(2) promoter-reporter gene construct. In these mice, the region -7,264/+253 of the HKalpha(2) 5'-flanking region controls expression of the reporter gene enhanced green fluorescent protein (EGFP). Patterns of HKalpha(2)/EGFP transgene expression were examined by fluorescence microscopy and immunoblotting. Of 10 major organs examined, EGFP immunoreactivity was detected abundantly in the kidney, and to a far lesser extent, in the brain and lung. Within the kidney, EGFP fluorescence was detected exclusively in the collecting ducts of transgenic mice and colocalized with the cellular distribution of both endogenous HKalpha(2) and aquaporin-2, consistent with the known expression pattern of endogenous HKalpha(2) in principal cells. Surprisingly, no transgene expression was evident by immunoblotting or fluorescence microscopy in the distal colon, the site of the highest endogenous HKalpha(2) expression. Although previous studies of steady-state mRNA levels suggested differences in HKalpha(2) gene regulation in the kidney and colon, our results provide the first direct evidence of differential transcriptional control of the HKalpha(2) gene in these organs and suggest that regions outside the 5'-flanking region or other regulatory factors play a role in HKalpha(2) expression in the distal colon.

    Funded by: NIDDK NIH HHS: R01-DK-47981

    American journal of physiology. Renal physiology 2004;286;6;F1171-7

  • No mutations in CACNA1A and ATP1A2 in probands with common types of migraine.

    Jen JC, Kim GW, Dudding KA and Baloh RW

    Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA. jjen@ucla.edu

    Background: Mutations in CACNA1A, encoding a neuronal calcium channel subunit, and ATP1A2, encoding a catalytic subunit of a sodium-potassium-ATPase, have been found in some families with dominantly inherited hemiplegic migraine.

    Objective: To determine the prevalence of mutations in these genes in individuals with different migraine syndromes.

    Design: Prospective screening study.

    Setting: University outpatient neurology clinic. Subjects Probands of 19 families with hemiplegic migraine, 7 with basilar migraine, 25 with migraine without aura, and 18 with migraine with aura, as well as 40 unaffected relatives of probands.

    Interventions: All known exons and flanking introns of CACNA1A and ATP1A2 were subjected to denaturing high-performance liquid chromatography analysis of polymerase chain reaction-amplified genomic DNA. Exons with atypical elution patterns were sequenced by standard techniques.

    Presence of mutations in CACNA1A and ATP1A2.

    Results: A single mutation (T666M) was found in CACNA1A in a patient with hemiplegic migraine and ataxia. No other mutation was identified in either gene. The frequency of a previously reported intronic insertion in ATP1A2 was not significantly different between patients with migraine and control subjects.

    Conclusion: These 2 genes are not associated with more common migraine syndromes and are not the most common hemiplegic migraine genes.

    Funded by: NIDCD NIH HHS: DC000162, DC05524

    Archives of neurology 2004;61;6;926-8

  • Variability of familial hemiplegic migraine with novel A1A2 Na+/K+-ATPase variants.

    Jurkat-Rott K, Freilinger T, Dreier JP, Herzog J, Göbel H, Petzold GC, Montagna P, Gasser T, Lehmann-Horn F and Dichgans M

    Department of Applied Physiology, Ulm University, Germany. karin.jurkat-rott@medizin.uni-ulm.de

    A1A2 Na+/K+-ATPase mutations cause familial hemiplegic migraine type 2 (FHM2). The authors identified three putative A1A2 mutations (D718N, R763H, P979L) and three that await validation (P796R, E902K, X1021R). Ten to 20% of FHM cases may be FHM2. A1A2 mutations have a penetrance of about 87%. D718N causes frequent, long-lasting HM, and P979L may cause recurrent coma. D718N and P979L may predispose to seizures and mental retardation. A1A2 does not play a major role in sporadic HM; only one variant, R383H, occurred in 1 of 24 cases.

    Neurology 2004;62;10;1857-61

  • Effect of resistance training on Na,K pump and Na+/H+ exchange protein densities in muscle from control and patients with type 2 diabetes.

    Dela F, Holten M and Juel C

    Department of Medical Physiology, University of Copenhagen, Copenhagen, Denmark.

    Ten patients with type 2 diabetes and seven controls were strength-trained with one leg for 30 min three times per week for 6 weeks. The training-induced changes in the protein densities of the Na,K-pump subunits and the Na+/H+ exchanger protein NHE1 were quantified with Western blotting of needle biopsy material obtained from trained and untrained legs of both groups. Training increased the bench press and knee-extensor force by 77+/-15 and 28+/-1%, respectively, in the control subjects, and by 75+/-7 and 42+/-8%, respectively, in the diabetics. In the control subjects the Na,K-pump isoform alpha1 was increased by 37% (P<0.05) in trained compared to untrained leg, and in the diabetics the alpha1 content was 45% higher (P=0.052) in trained compared to untrained leg. For the alpha2 isoform the corresponding values were 21% and 41% (P<0.05), respectively. The content of the beta1 subunit in the control subjects was 33% higher (P<0.05) in trained compared to untrained leg, and 47% higher (P=0.06) in trained compared to untrained leg in the diabetics. Thus, a limited amount of strength-training is able to increase the Na,K-pump subunit and isoform content both in controls and in patients with type 2 diabetes.

    Pflugers Archiv : European journal of physiology 2004;447;6;928-33

  • Complete sequencing and characterization of 21,243 full-length human cDNAs.

    Ota T, Suzuki Y, Nishikawa T, Otsuki T, Sugiyama T, Irie R, Wakamatsu A, Hayashi K, Sato H, Nagai K, Kimura K, Makita H, Sekine M, Obayashi M, Nishi T, Shibahara T, Tanaka T, Ishii S, Yamamoto J, Saito K, Kawai Y, Isono Y, Nakamura Y, Nagahari K, Murakami K, Yasuda T, Iwayanagi T, Wagatsuma M, Shiratori A, Sudo H, Hosoiri T, Kaku Y, Kodaira H, Kondo H, Sugawara M, Takahashi M, Kanda K, Yokoi T, Furuya T, Kikkawa E, Omura Y, Abe K, Kamihara K, Katsuta N, Sato K, Tanikawa M, Yamazaki M, Ninomiya K, Ishibashi T, Yamashita H, Murakawa K, Fujimori K, Tanai H, Kimata M, Watanabe M, Hiraoka S, Chiba Y, Ishida S, Ono Y, Takiguchi S, Watanabe S, Yosida M, Hotuta T, Kusano J, Kanehori K, Takahashi-Fujii A, Hara H, Tanase TO, Nomura Y, Togiya S, Komai F, Hara R, Takeuchi K, Arita M, Imose N, Musashino K, Yuuki H, Oshima A, Sasaki N, Aotsuka S, Yoshikawa Y, Matsunawa H, Ichihara T, Shiohata N, Sano S, Moriya S, Momiyama H, Satoh N, Takami S, Terashima Y, Suzuki O, Nakagawa S, Senoh A, Mizoguchi H, Goto Y, Shimizu F, Wakebe H, Hishigaki H, Watanabe T, Sugiyama A, Takemoto M, Kawakami B, Yamazaki M, Watanabe K, Kumagai A, Itakura S, Fukuzumi Y, Fujimori Y, Komiyama M, Tashiro H, Tanigami A, Fujiwara T, Ono T, Yamada K, Fujii Y, Ozaki K, Hirao M, Ohmori Y, Kawabata A, Hikiji T, Kobatake N, Inagaki H, Ikema Y, Okamoto S, Okitani R, Kawakami T, Noguchi S, Itoh T, Shigeta K, Senba T, Matsumura K, Nakajima Y, Mizuno T, Morinaga M, Sasaki M, Togashi T, Oyama M, Hata H, Watanabe M, Komatsu T, Mizushima-Sugano J, Satoh T, Shirai Y, Takahashi Y, Nakagawa K, Okumura K, Nagase T, Nomura N, Kikuchi H, Masuho Y, Yamashita R, Nakai K, Yada T, Nakamura Y, Ohara O, Isogai T and Sugano S

    Helix Research Institute, 1532-3 Yana, Kisarazu, Chiba 292-0812, Japan.

    As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

    Nature genetics 2004;36;1;40-5

  • Alternating hemiplegia of childhood: a syndrome inherited with an autosomal dominant trait.

    Kanavakis E, Xaidara A, Papathanasiou-Klontza D, Papadimitriou A, Velentza S and Youroukos S

    Athens University, Aghia Sophia, Children's Hospital, Greece. ekanavak@cc.uoa.gr

    Alternating hemiplegia of childhood is a rare disorder characterized by recurrent attacks of hemiplegia affecting either side of the body, oculomotor and autonomic disturbances, movement disorders, and progressive cognitive impairment. We report on one family with autosomal dominant alternating hemiplegia. The disorder was first recognized in a 9-year-old child, the third son of the family, who presented with learning disability, tonic-clonic seizures, dystonic attacks, and episodes of alternating hemiplegia starting at the age of 2 1/2 years. His mother and three brothers had similar symptoms. The maternal uncle, who has learning disability, had experienced multiple dystonic attacks. Tests performed on the family, including computerized tomography, magnetic resonance imaging, and magnetic resonance angiography of the brain as well as metabolic evaluation, were normal. Cytogenetic analysis was normal and mitochondrial DNA analysis revealed no deletions or mutations in the four affected family members and the grandmother. An autosomal dominant mode of inheritance is suggested by the fact that both sexes are affected in two generations.

    Developmental medicine and child neurology 2003;45;12;833-6

  • Relation of erythrocyte Na+-K+ ATPase activity and cholesterol and oxidative stress in patients with type 2 diabetes mellitus.

    Konukoglu D, Kemerli GD, Sabuncu T and Hatemi H

    Department of Biochemistry, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey. dkonuk@yahoo.com

    Background: Diabetic patients are at high risk of atherosclerotic complications, and factors associated with this include hypercholesterolemia, hemorheologic disturbances in erythrocytes and oxidative stress. We, therefore, carried out a study in type 2 diabetic patients to determine the relationships of erythrocyte Na+-K+ ATPase activity, plasma cholesterol and oxidative stress in this population.

    Methods: Erythrocyte Na+-K+ ATPase activity and its relationship between plasma cholesterol and thiobarbituric acid reactive substance (TBARS, a marker of oxidative stress) were studied in type 2 diabetic patients with (n = 26) or without angiopathy (n = 30). Na+-K+ ATPase activity was measured by a colorimetric enzymatic method. Plasma TBARS levels were determined spectrophotometrically. Diabetic patients were classified according to plasma cholesterol concentrations as normo- or hypercholesterolemic (plasma total cholesterol > 5.18 mmol/L).

    Results: Diabetic patients with or without angiopathy had lower erythrocyte Na+-K+ ATPase activity (p < 0.001 and p < 0.001 respectively) and higher plasma TBARS levels than healthy subjects (n = 20) (p < 0.001 and p < 0.001 respectively). Na+-K+ ATPase activity in the diabetic patients with angiopathy was lower than in the diabetic patients without angiopathy (p < 0.001). In the diabetic patients both with and without angiopathy, hypercholesterolemic patients had lower erythrocyte Na+-K+ ATPase activity and higher plasma TBARS levels than normocholesterolemic patients (p < 0.001, p < 0.001 respectively) There was no difference in the plasma TBARS concentrations between diabetic patients with and without angiopathy. There were negative correlations between erythrocyte Na+-K+ ATPase activity and both plasma cholesterol (r = -0.72) and plasma TBARS (r = -0.46) and a positive correlation between plasma cholesterol and TBARS (r = 0.42).

    Conclusions: Elevated plasma cholesterol may be responsible for the inhibition of erythrocyte Na+-K+ ATPase activity. Together with elevated cholesterol, free radical-induced mechanisms may be involved in the inhibition of Na+-K+ ATPase activity.

    Clinical and investigative medicine. Medecine clinique et experimentale 2003;26;6;279-84

  • Novel mutations in the Na+, K+-ATPase pump gene ATP1A2 associated with familial hemiplegic migraine and benign familial infantile convulsions.

    Vanmolkot KR, Kors EE, Hottenga JJ, Terwindt GM, Haan J, Hoefnagels WA, Black DF, Sandkuijl LA, Frants RR, Ferrari MD and van den Maagdenberg AM

    Department of Human Genetics, Leiden University Medical Centre, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands.

    Familial hemiplegic migraine (FHM) is a rare, severe, autosomal dominant subtype of migraine with aura. Up to 75% of FHM families have a mutation in the P/Q-type calcium channel Ca(v)2.1 subunit CACNA1A gene on chromosome 19p13. Some CACNA1A mutations also may cause epilepsy. Here, we describe novel missense mutations in the ATP1A2 Na(+),K(+)-ATPase pump gene on chromosome 1q23 in two families with FHM. The M731T mutation was found in a family with pure FHM. The R689Q mutation was identified in a family in which FHM and benign familial infantile convulsions partially cosegregate. In this family, all available affected family members with FHM, benign familial infantile convulsions, or both, carry the ATP1A2 mutation. Like FHM linked to 19p13, FHM linked to 1q23 also involves dysfunction of ion transportation and epilepsy is part of its phenotypic spectrum.

    Annals of neurology 2003;54;3;360-6

  • Degeneration of the amygdala/piriform cortex and enhanced fear/anxiety behaviors in sodium pump alpha2 subunit (Atp1a2)-deficient mice.

    Ikeda K, Onaka T, Yamakado M, Nakai J, Ishikawa TO, Taketo MM and Kawakami K

    Department of Biology Jichi Medical School, Kawachi, Tochigi 329-0498, Japan.

    The sodium pump is the enzyme responsible for the maintenance of Na+ and K+ gradients across the cell membrane. Four isoforms of the catalytic alpha subunit have been identified, but their individual roles remain essentially unknown. To investigate the necessary functions of the alpha2 subunit in vivo, we generated and analyzed mice defective in the alpha2 subunit gene. Mice homozygous for the alpha2 mutation died just after birth and displayed selective neuronal apoptosis in the amygdala and piriform cortex. In these regions, high expression of c-Fos before apoptosis indicated neural hyperactivity, and re-uptake of glutamic acid and GABA into P2 fraction containing crude synaptosome was impaired. These results indicate that the alpha2 subunit plays a critical role regulating neural activity in the developing amygdala and piriform cortex. Further supporting a role of the alpha2 subunit in the function of the amygdala, heterozygous adult mice showed augmented fear/anxiety behaviors and enhanced neuronal activity in the amygdala and piriform cortex after conditioned fear stimuli.

    The Journal of neuroscience : the official journal of the Society for Neuroscience 2003;23;11;4667-76

  • Na+-K+-ATPase alpha 2-gene and skeletal muscle characteristics in response to long-term overfeeding.

    Ukkola O, Joanisse DR, Tremblay A and Bouchard C

    Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808-4124, USA.

    The role of Na(+)-K(+)-ATPase alpha2-gene BglII polymorphism in the changes of skeletal muscle metabolic properties after a 100-day overfeeding protocol conducted with 12 pairs of monozygotic twins is reported. The activities of oxoglutarate dehydrogenase (OGDH) and phosphofructokinase (PFK) were determined from muscle biopsies. A larger increase in the total fat mass (127 vs. 61%) (P < 0.05) and low-density lipoprotein cholesterol (20 vs. 0.7%) (P = 0.05) in 8.0/8.0-kb [3.3-kb negative (-); n = 7 pairs] than in 8.0/3.3 + 3.3/3.3-kb [3.3-kb positive (+); n = 5 pairs] subjects was observed. OGDH activity decreased in 3.3-kb(-) (-15%), whereas PFK (+26%) as well as the PFK-to-OGDH ratio (90%) increased. In contrast, among 3.3-kb(+), OGDH increased (+54%) together with a decrease in PFK (-1%) and PFK-to-OGDH ratio (-5%). These changes were significantly different between genotypes (P from <0.05 to 0.01). In conclusion, fat mass, low-density lipoprotein cholesterol, and skeletal muscle glycolytic-to-oxidative enzyme ratio increased more in the alpha2-gene 3.3-kb(-) subjects with overfeeding, suggesting more unfavorable metabolic changes compared with the 3.3-kb(+) subjects.

    Funded by: NIDDK NIH HHS: DK-34624

    Journal of applied physiology (Bethesda, Md. : 1985) 2003;94;5;1870-4

  • Structural basis for alpha1 versus alpha2 isoform-distinct behavior of the Na,K-ATPase.

    Segall L, Javaid ZZ, Carl SL, Lane LK and Blostein R

    Department of Biochemistry, McGill University, Montreal, Quebec H3G 1A4, Canada.

    We showed earlier that the kinetic behavior of the alpha2 isoform of the Na,K-ATPase differs from the ubiquitous alpha1 isoform primarily by a shift in the steady-state E(1)/E(2) equilibrium of alpha2 in favor of E(1) form(s). The aim of the present study was to identify regions of the alpha chain that confer the alpha1/alpha2 distinct behavior using a mutagenesis and chimera approach. Criteria to assess shifts in conformational equilibrium included (i) K(+) sensitivity of Na-ATPase measured at micromolar ATP, under which condition E(2)(K(+)) --> E(1) + K(+) becomes rate-limiting, (ii) changes in K'(ATP) for low affinity ATP binding, (iii) vanadate sensitivity of Na,K-ATPase activity, and (iv) the rate of the partial reaction E(1)P --> E(2)P. We first confirmed that interactions between the cytoplasmic domains of alpha2 that modulate conformational shifts are fundamentally similar to those of alpha1, suggesting that the predilection of alpha2 for E(1) state(s) is due to differences in primary structure of the two isoforms. Kinetic behavior of the alpha1/alpha2 chimeras indicates that the difference in E(1)/E(2) poise of the two isoforms cannot be accounted for by their notably distinct N termini, but rather by the front segment extending from the cytoplasmic N terminus to the C-terminal end of the extracellular loop between transmembranes 3 and 4, with a lesser contribution of the alpha1/alpha2 divergent portion within the M4-M5 loop near the ATP binding domain. In addition, we show that the E(1) shift of alpha2 results primarily from differences in the conformational transition of the dephosphoenzyme, (E(2)(K(+)) --> E(1) + K(+)), rather than phosphoenzyme (E(1)P --> E(2)P).

    Funded by: NHLBI NIH HHS: HL 49204

    The Journal of biological chemistry 2003;278;11;9027-34

  • Haploinsufficiency of ATP1A2 encoding the Na+/K+ pump alpha2 subunit associated with familial hemiplegic migraine type 2.

    De Fusco M, Marconi R, Silvestri L, Atorino L, Rampoldi L, Morgante L, Ballabio A, Aridon P and Casari G

    Human Molecular Genetics Unit, Dibit-San Raffaele Scientific Institute, Via Olgettina 58, 20132 Milan, Italy.

    Headache attacks and autonomic dysfunctions characterize migraine, a very common, disabling disorder with a prevalence of 12% in the general population of Western countries. About 20% of individuals affected with migraine experience aura, a visual or sensory-motor neurological dysfunction that usually precedes or accompanies the headache. Although the mode of transmission is controversial, population-based and twin studies have implicated genetic factors, especially in migraine with aura. Familial hemiplegic migraine is a hereditary form of migraine characterized by aura and some hemiparesis. Here we show that mutations in the gene ATP1A2 that encodes the alpha2 subunit of the Na+/K+ pump are associated with familial hemiplegic migraine type 2 (FHM2) linked to chromosome 1q23 (OMIM 602481). Functional data indicate that the putative pathogenetic mechanism is triggered by a loss of function of a single allele of ATP1A2. This is the first report associating mutations of Na+K+ pump subunits to genetic diseases.

    Funded by: Telethon: F.1, TGM03S01, TGM06S01

    Nature genetics 2003;33;2;192-6

  • Ion pumps in polarized cells: sorting and regulation of the Na+, K+- and H+, K+-ATPases.

    Dunbar LA and Caplan MJ

    Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.

    The physiologic function of an ion transport protein is determined, in part, by its subcellular localization and by the cellular mechanisms that modulate its activity. The Na(+),K(+)-ATPase and the H(+),K(+)-ATPases are closely related members of the P-type family of ion transporting ATPases. Despite their homology, these pumps are sorted to different domains in polarized epithelial cells, and their enzymatic activities are subject to distinct regulatory pathways. The molecular signals responsible for these properties have begun to be elucidated. It appears that a complex array of inter- and intramolecular interactions govern trafficking, distribution, and catalytic capacities of these proteins.

    Funded by: NIDDK NIH HHS: DK-17433; NIGMS NIH HHS: GM-42136

    The Journal of biological chemistry 2001;276;32;29617-20

  • Relation of alleles of the sodium-potassium adenosine triphosphatase alpha 2 gene with blood pressure and lead exposure.

    Glenn BS, Stewart WF, Schwartz BS and Bressler J

    Department of Neurology, Kennedy Krieger Research Institute, Johns Hopkins Medical Institutions, Baltimore, MD, USA.

    Lead is associated with elevated blood pressure, although the mechanism of action is unknown. Genetic differences in sodium-potassium adenosine triphosphatase (Na(+)-K(+)ATPase) could explain some of the variation in the strength of the blood pressure-blood lead relation that has been observed in previous studies. In 1996-1997, the authors studied the association of blood pressure, hypertension prevalence, and polymorphisms in the gene for the alpha 2 subunit of Na(+)-K(+)ATPase (ATP1A2) among 220 former organolead manufacturing workers from New Jersey. Subjects were genotyped for a restriction fragment length polymorphism (RFLP) on the ATP1A2 gene. The association between blood lead and blood pressure was stronger among persons who were homozygous for the variant allele. Genotype was also associated with hypertension (adjusted odds ratio = 7.7; 95% confidence interval: 1.9, 31.4). Finally, the variant allele was 1.8 times more common among African Americans than among Caucasians. The RFLP may indicate susceptibility to the effect of lead on blood pressure. Moreover, the alpha 2 gene (or a closely linked gene) may contribute to the pathophysiology of hypertension. However, because the number of subjects (especially African Americans) with the susceptible genotype in this study was small, these observations should be considered preliminary.

    Funded by: NIA NIH HHS: R01AG10785; NIEHS NIH HHS: 1P01ES08131-01A1, ES07980-03, T32 ES07141

    American journal of epidemiology 2001;153;6;537-45

  • The Na(+)-K(+)-ATPase alpha2 gene and trainability of cardiorespiratory endurance: the HERITAGE family study.

    Rankinen T, Pérusse L, Borecki I, Chagnon YC, Gagnon J, Leon AS, Skinner JS, Wilmore JH, Rao DC and Bouchard C

    Pennington Biomedical Research Center, Human Genomics Laboratory, Baton Rouge, Louisiana 70808-4124, USA.

    The Na(+)-K(+)-ATPase plays an important role in the maintenance of electrolyte balance in the working muscle and thus may contribute to endurance performance. This study aimed to investigate the associations between genetic variants at the Na(+)-K(+)-ATPase alpha2 locus and the response (Delta) of maximal oxygen consumption (VO(2 max)) and maximal power output (W(max)) to 20 wk of endurance training in 472 sedentary Caucasian subjects from 99 families. VO(2 max) and W(max) were measured during two maximal cycle ergometer exercise tests before and again after the training program, and restriction fragment length polymorphisms at the Na(+)-K(+)-ATPase alpha2 (exons 1 and 21-22 with Bgl II) gene were typed. Sibling-pair linkage analysis revealed marginal evidence for linkage between the alpha2 haplotype and DeltaVO(2 max) (P = 0.054) and stronger linkages between the alpha2 exon 21-22 marker (P = 0.005) and alpha2 haplotype (P = 0.003) and DeltaW(max). In the whole cohort, DeltaVO(2 max) in the 3.3-kb homozygotes of the exon 1 marker (n = 5) was 41% lower than in the 8.0/3.3-kb heterozygotes (n = 87) and 48% lower than in the 8.0-kb homozygotes (n = 380; P = 0.018, adjusted for age, gender, baseline VO(2 max), and body weight). Among offspring, 10.5/10.5-kb homozygotes (n = 14) of the exon 21-22 marker showed a 571 +/- 56 (SE) ml O(2)/min increase in VO(2 max), whereas the increases in the 10.5/4.3-kb (n = 93) and 4.3/4.3-kb (n = 187) genotypes were 442 +/- 22 and 410 +/- 15 ml O(2)/min, respectively (P = 0.017). These data suggest that genetic variation at the Na(+)-K(+)-ATPase alpha2 locus influences the trainability of VO(2 max) in sedentary Caucasian subjects.

    Funded by: NHLBI NIH HHS: HL45670, HL47317, HL47323; ...

    Journal of applied physiology (Bethesda, Md. : 1985) 2000;88;1;346-51

  • Linkage and association of the sodium potassium-adenosine triphosphatase alpha2 and beta1 genes with respiratory quotient and resting metabolic rate in the Québec Family Study.

    Katzmarzyk PT, Rankinen T, Pérusse L, Dériaz O, Tremblay A, Borecki I, Rao DC and Bouchard C

    Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Quebec, Canada.

    The purpose of this study was to examine the relationship between the alpha2 (exon 1 and exon 21-22 with BglII) and beta1 (MspI and PvuII) genes of the sodium potassium adenosine triphosphatase and resting metabolic rate (RMR) and respiratory quotient (RQ). The sample included 582 participants from 171 families of the Québec Family Study. RMR and RQ were adjusted for age, sex, fat mass, and fat free mass. Sib-pair analyses indicated a significant linkage between RQ and the alpha2 exon 1 marker (P = 0.03) and the alpha2 exon 21-22 marker (P = 0.02). No linkage was detected between the beta1 markers and either RMR or RQ, whereas RMR was not linked with the alpha2 makers. There was a significant interaction (P < 0.0003) between alpha2 exon 1 carrier status and age group [younger (< 45 yr) vs. older (> or = 45 yr) adults] for RQ. The association between carrier status and RQ was significant in younger adults (RQ = 0.76 in carriers vs. 0.80 in noncarriers, P < 0.0001) but was not in older adults (RQ = 0.81 in carriers vs. 0.80 in noncarriers). The alpha2 exon 1 gene accounted for approximately 9.1% and 0.3% of the variance in RQ in younger and older adults, respectively. The results suggest that the sodium potassium adenosine triphosphatase alpha2 gene may play a role in fuel oxidation, particularly in younger individuals.

    Funded by: NCRR NIH HHS: 1-P41-RR03655

    The Journal of clinical endocrinology and metabolism 1999;84;6;2093-7

  • Prediction of the coding sequences of unidentified human genes. XI. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro.

    Nagase T, Ishikawa K, Suyama M, Kikuno R, Miyajima N, Tanaka A, Kotani H, Nomura N and Ohara O

    Kazusa DNA Research Institute, Kisarazu, Chiba, Japan.

    In our series of projects for accumulating sequence information on the coding sequences of unidentified human genes, we have newly determined the sequences of 100 cDNA clones from a set of size-fractionated human brain cDNA libraries, and predicted the coding sequences of the corresponding genes, named KIAA0711 to KIAA0810. These cDNA clones were selected according to their coding potentials of large proteins (50 kDa and more) in vitro. The average sizes of the inserts and corresponding open reading frames were 4.3 kb and 2.6 kb (869 amino acid residues), respectively. Sequence analyses against the public databases indicated that the predicted coding sequences of 78 genes were similar to those of known genes, 64% of which (50 genes) were categorized as proteins functionally related to cell signaling/communication, cell structure/motility and nucleic acid management. As additional information concerning genes characterized in this study, the chromosomal locations of the clones were determined by using human-rodent hybrid panels and the expression profiles among 10 human tissues were examined by reverse transcription-coupled polymerase chain reaction which was substantially improved by enzyme-linked immunosorbent assay.

    DNA research : an international journal for rapid publication of reports on genes and genomes 1998;5;5;277-86

  • Mapping of a second locus for familial hemiplegic migraine to 1q21-q23 and evidence of further heterogeneity.

    Ducros A, Joutel A, Vahedi K, Cecillon M, Ferreira A, Bernard E, Verier A, Echenne B, Lopez de Munain A, Bousser MG and Tournier-Lasserve E

    INSERM U25, Faculté de Médecine Necker, Hôpital Lariboisiere, Paris, France.

    Familial hemiplegic migraine (FHM) is an autosomal dominant variety of migraine with aura. We previously mapped an FHM gene on the short arm of chromosome 19. Mutations in this gene, recently shown to be the alpha1 subunit of a P/Q-type voltage-dependent calcium channel, CACNL1A4, are involved in approximately 50% of unselected FHM families and in all families where migraine attacks are associated with permanent cerebellar ataxia. As a first step toward the identification of other FHM genes, we conducted a genetic linkage analysis in one large French pedigree and showed significant linkage to two microsatellite markers D1S2635 (Zmax: 3.33 at theta = 0.05) and D1S2705 (Zmax: 3.64 at theta = 0.05), establishing the existence of a second locus for FHM (FHM2) on chromosome 1q21-q23. Analysis of six additional FHM families favored linkage to this locus in two of them; linkage was excluded in the last four families, indicating further heterogeneity. Chromosome 1-linked families differ from the ones linked to chromosome 19, because penetrance in those families is much lower, and in some of their members, epileptic seizures occur during severe migraine attacks.

    Annals of neurology 1997;42;6;885-90

  • Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library.

    Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, Suyama A and Sugano S

    International and Interdisciplinary Studies, The University of Tokyo, Japan.

    Using 'oligo-capped' mRNA [Maruyama, K., Sugano, S., 1994. Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides. Gene 138, 171-174], whose cap structure was replaced by a synthetic oligonucleotide, we constructed two types of cDNA library. One is a 'full length-enriched cDNA library' which has a high content of full-length cDNA clones and the other is a '5'-end-enriched cDNA library', which has a high content of cDNA clones with their mRNA start sites. The 5'-end-enriched library was constructed especially for isolating the mRNA start sites of long mRNAs. In order to characterize these libraries, we performed one-pass sequencing of randomly selected cDNA clones from both libraries (84 clones for the full length-enriched cDNA library and 159 clones for the 5'-end-enriched cDNA library). The cDNA clones of the polypeptide chain elongation factor 1 alpha were most frequently (nine clones) isolated, and more than 80% of them (eight clones) contained the mRNA start site of the gene. Furthermore, about 80% of the cDNA clones of both libraries whose sequence matched with known genes had the known 5' ends or sequences upstream of the known 5' ends (28 out of 35 for the full length-enriched library and 51 out of 62 for the 5'-end-enriched library). The longest full-length clone of the full length-enriched cDNA library was about 3300 bp (among 28 clones). In contrast, seven clones (out of the 51 clones with the mRNA start sites) from the 5'-end-enriched cDNA library came from mRNAs whose length is more than 3500 bp. These cDNA libraries may be useful for generating 5' ESTs with the information of the mRNA start sites that are now scarce in the EST database.

    Gene 1997;200;1-2;149-56

  • Partial cosegregation of familial hemiplegic migraine and a benign familial infantile epileptic syndrome.

    Terwindt GM, Ophoff RA, Lindhout D, Haan J, Halley DJ, Sandkuijl LA, Brouwer OF, Frants RR and Ferrari MD

    Department of Neurology, Leiden University Medical Center, The Netherlands.

    Purpose: We studied a large Dutch-Canadian family, in which two very rare hereditary paroxysmal neurologic disorders, familial hemiplegic migraine (FHM) and a "benign familial infantile epileptic syndrome" concur and partially cosegregate. FHM is a dominantly inherited subtype of migraine with attacks of hemiparesis, linked to chromosome 19p13 in 50% of the families tested. Recently mutations in a brain-specific P/Q-type Ca2+ channel alpha1 subunit gene (CACNL1A4) were identified in families with chromosome 19-linked FHM. The infantile epileptic syndrome resembles to two other dominantly inherited benign epilepsies occurring in the first year of life, benign familial neonatal convulsions (BFNC), assigned to chromosomes 20q13.2 and 8q, and benign infantile familial convulsions (BIFC), as yet unlinked.

    Methods: Linkage analysis was performed for the known locations of FHM and BFNC. The question whether the two conditions in this family can be caused by a single gene defect was addressed by additional linkage analysis.

    Results: We excluded linkage of the infantile convulsions to markers on chromosome 20q13.2, 8q, or 19p13. This indicates the existence of a third locus for benign familial convulsions in the first year of life. Linkage of FHM to these markers was not formally excluded but seems very unlikely. Statistical analysis of whether, in this family, both conditions are caused by a single gene defect was inconclusive.

    Conclusions: We describe a "benign familial infantile epileptic syndrome" with attacks of FHM at a later age. Further genetic studies in this family may help to unravel the genetic basis of epilepsy or migraine or both.

    Epilepsia 1997;38;8;915-21

  • Na,K-ATPase subunit isoforms in human reticulocytes: evidence from reverse transcription-PCR for the presence of alpha1, alpha3, beta2, beta3, and gamma.

    Stengelin MK and Hoffman JF

    Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.

    The objective of this study has been to determine which Na,K-ATPase isoforms are expressed in red blood cells and whether kinetic differences in the uncoupled sodium efflux mode between the human red blood cell Na,K-ATPase and other preparations can be explained by differences in the underlying subunit composition. To this end, human reticulocyte RNA was isolated, reverse transcribed, amplified by PCR and appropriate primers, and sequenced. Primers from highly conserved areas as well as isoform-specific primers were used. The alpha1 and alpha3 isoforms of the alpha subunit, and the beta2 and beta3 isoforms of the beta subunit were found. The complete coding regions of the cDNAs for the reticulocyte subunits were sequenced from overlapping PCR fragments. No difference was found between the reticulocyte isoforms and the ones already known. The fact that we found beta2 but not beta1 in reticulocyte single-stranded cDNA, and beta1 but not beta2 in a leukocyte library indicates that leukocyte contamination of our reticulocyte preparation was negligible. Analysis of a human bone marrow library showed that alpha1, alpha2, and alpha3 as well as all three beta isoforms were present. The extent to which the kinetic properties of uncoupled sodium efflux might depend on different isoform combinations is not yet known.

    Funded by: NHLBI NIH HHS: HL52720

    Proceedings of the National Academy of Sciences of the United States of America 1997;94;11;5943-8

  • Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides.

    Maruyama K and Sugano S

    Institute of Medical Science, University of Tokyo, Japan.

    We have devised a method to replace the cap structure of a mRNA with an oligoribonucleotide (r-oligo) to label the 5' end of eukaryotic mRNAs. The method consists of removing the cap with tobacco acid pyrophosphatase (TAP) and ligating r-oligos to decapped mRNAs with T4 RNA ligase. This reaction was made cap-specific by removing 5'-phosphates of non-capped RNAs with alkaline phosphatase prior to TAP treatment. Unlike the conventional methods that label the 5' end of cDNAs, this method specifically labels the capped end of the mRNAs with a synthetic r-oligo prior to first-strand cDNA synthesis. The 5' end of the mRNA was identified quite simply by reverse transcription-polymerase chain reaction (RT-PCR).

    Gene 1994;138;1-2;171-4

  • Expression of alpha isoforms of the Na,K-ATPase in human heart.

    Zahler R, Gilmore-Hebert M, Baldwin JC, Franco K and Benz EJ

    Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510.

    We studied expression of isoforms of Na,K-ATPase in normal and diseased human hearts. Na,K-ATPase alpha-isoform mRNA in samples from normal human left ventricle (LV) was composed of 62.5%, alpha 1, 15% alpha 2 and 22.5% alpha 3 on average. There was an increase in expression of the alpha 3 isoform in samples from failing hearts, but expression of all three isoforms decreased in pressure-overloaded right ventricle (RV).

    Funded by: NHLBI NIH HHS: NHLBI HL-01686

    Biochimica et biophysica acta 1993;1149;2;189-94

  • Molecular genetics of Na,K-ATPase.

    Lingrel JB, Orlowski J, Shull MM and Price EM

    Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Ohio 45267.

    Researchers in the past few years have successfully used molecular-genetic approaches to determine the primary structures of several P-type ATPases. The amino-acid sequences of distinct members of this class of ion-transport ATPases (Na,K-, H,K-, and Ca-ATPases) have been deduced by cDNA cloning and sequencing. The Na,K-ATPase belongs to a multiple gene family, the principal diversity apparently resulting from distinct catalytic alpha isoforms. Computer analyses of the hydrophobicity and potential secondary structure of the alpha subunits and primary sequence comparisons with homologs from various species as well as other P-type ATPases have identified common structural features. This has provided the molecular foundation for the design of models and hypotheses aimed at understanding the relationship between structure and function. Development of a hypothetical transmembrane organization for the alpha subunit and application of site-specific mutagenesis techniques have allowed significant progress to be made toward identifying amino acids involved in cardiac glycoside resistance and possibly binding. However, the complex structural and functional features of this protein indicate that extensive research is necessary before a clear understanding of the molecular basis of active cation transport is achieved. This is complicated further by the paucity of information regarding the structural and functional contributions of the beta subunit. Until such information is obtained, the proposed model and functional hypotheses should be considered judiciously. Considerable progress also has been made in characterizing the regulatory complexity involved in expression of multiple alpha-isoform and beta-subunit genes in various tissues and cells during development and in response to hormones and cations. The regulatory mechanisms appear to function at several molecular levels, involving transcriptional, posttranscriptional, translational, and posttranslational processes in a tissue- or cell-specific manner. However, much research is needed to precisely define the contributions of each of these mechanisms. Recent isolation of the genes for these subunits provides the framework for future advances in this area. Continued application of biochemical, biophysical, and molecular genetic techniques is required to provide a detailed understanding of the mechanisms involved in cation transport of this biologically and pharmacologically important enzyme.

    Progress in nucleic acid research and molecular biology 1990;38;37-89

  • Characterization of the human Na,K-ATPase alpha 2 gene and identification of intragenic restriction fragment length polymorphisms.

    Shull MM, Pugh DG and Lingrel JB

    Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Ohio 45267-0524.

    We have determined the structure of the gene that encodes the alpha 2 isoform of the human Na,K-ATPase. The gene contains 23 exons and spans approximately 25 kilobases. The amino acid sequence of the human alpha 2 isoform deduced from the genomic sequence exhibits 99% identity to the rat alpha 2 isoform. One of the nine amino acid differences between the human and rat sequences occurs at an amino acid position which is known to be involved in species differences in sensitivity of the alpha 1 isoform to cardiac glycosides. Approximately 1500 base pairs of sequence flanking the 5' end of the alpha 2 gene have been determined. This region contains numerous potential AP-1, AP-2, and NF-1-binding sites, a potential Sp1 recognition site, and several sequences that are similar to the glucocorticoid receptor-binding site. The transcription start site was mapped by primer extension and S1 nuclease protection analyses of RNA from human brain, skeletal muscle, and heart. Multiple transcription initiation sites are clustered between residues -104 to -99 relative to the translation initiation codon. A potential TATA box is located 29 base pairs upstream of the first transcription initiation site. Immediately 5' to the apparent TATA box is a 35-base pair polypurine.polypyrimidine tract containing an imperfect mirror repeat which resembles sequences that form triple-stranded structures. Two intragenic DNA probes which detect restriction fragment length polymorphisms associated with the alpha 2 gene have been identified. These probes will be useful in genetic linkage analyses designed to define the possible role of the Na,K-ATPase in certain hereditary disorders.

    Funded by: NHLBI NIH HHS: HL28573

    The Journal of biological chemistry 1989;264;29;17532-43

  • Family of human Na+,K+-ATPase genes. Structure of the putative regulatory region of the alpha+-gene.

    Sverdlov ED, Bessarab DA, Malyshev IV, Petrukhin KE, Smirnov YuV, Ushkaryov YuA, Monastyrskaya GS, Broude NE and Modyanov NN

    Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences, Moscow.

    The primary structure of the putative regulatory region of a gene of the Na+,K+-ATPase multigene family in the human genome has been determined. This region includes the first exon with all of the untranslatable sequence of mRNA and a dozen nucleotides, coding for the first four amino acids of the hypothetic precursor of the alpha+-subunit. The entire region comprises over 1400 bp. The possible role of specific nucleotide blocks within this region in comparison with other genes is discussed.

    FEBS letters 1989;244;2;481-3

  • Chromosomal localization of human Na+, K+-ATPase alpha- and beta-subunit genes.

    Yang-Feng TL, Schneider JW, Lindgren V, Shull MM, Benz EJ, Lingrel JB and Francke U

    Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510.

    Na+, K+-ATPase is a heterodimeric enzyme responsible for the active maintenance of sodium and potassium gradients across the plasma membrane. Recently, cDNAs for several tissue-specific isoforms of the larger catalytic alpha-subunit and the smaller beta-subunit have been cloned. We have hybridized rat brain and human kidney cDNA probes, as well as human genomic isoform-specific DNA fragments, to Southern filters containing panels of rodent X human somatic cell hybrid lines. The results obtained have allowed us to assign the loci for the ubiquitously expressed alpha-chain (ATP1A1) to human chromosome 1, region 1p21----cen, and for the alpha 2 isoform that predominates in neural and muscle tissues (ATP1A2) to chromosome 1, region cen----q32. A common PstI RFLP was detected with the ATP1A2 probe. The alpha 3 gene, which is expressed primarily in neural tissues (ATP1A3), was assigned to human chromosome 19. A fourth alpha gene of unknown function (alpha D) that was isolated by molecular cloning (ATP1AL1) was mapped to chromosome 13. Although evidence to date had suggested a single gene for the beta-subunit, we found hybridizing restriction fragments derived from two different human chromosomes. On the basis of knowledge of conserved linkage groups on human and murine chromosomes, we propose that the coding gene ATP 1B is located on the long arm of human chromosome 1 and that the sequence on human chromosome 4 (ATP 1BL1) is either a related gene or a pseudogene.

    Funded by: NHLBI NIH HHS: HL28573; NIGMS NIH HHS: GM26105, T32GM07439

    Genomics 1988;2;2;128-38

  • The family of human Na+,K+-ATPase genes. No less than five genes and/or pseudogenes related to the alpha-subunit.

    Sverdlov ED, Monastyrskaya GS, Broude NE, Ushkaryov YuA, Allikmets RL, Melkov AM, Smirnov YuV, Malyshev IV, Dulobova IE, Petrukhin KE et al.

    Five different nucleotide sequences have been found in the human genome homologous to the gene of the alpha-subunit of Na+,K+-ATPase. A comparative analysis of the primary structure of these genes in the region 749-1328 (in coordinates of cDNA from the pig alpha-subunit) is presented.

    FEBS letters 1987;217;2;275-8

  • Multiple genes encode the human Na+,K+-ATPase catalytic subunit.

    Shull MM and Lingrel JB

    A human genomic library was constructed and screened with hybridization probes derived from sheep and rat cDNAs encoding the alpha and alpha(+) isoforms, respectively, of the Na+,K+-ATPase catalytic subunit. Genomic sequences spanning 150 kilobases were isolated. Four genes, designated alpha A, alpha B, alpha C, and alpha D, each 20-25 kilobases in length, were identified by restriction mapping, Southern blot hybridization analysis, and limited DNA sequencing. We present evidence that two of these genes, alpha A and alpha B, encode the alpha and alpha(+) isoforms, respectively. The other genes, alpha C and alpha D, one of which is physically linked to the alpha(+) gene, exhibit nucleotide and amino acid homology to Na+,K+-ATPase catalytic subunit cDNA sequences but do not correspond to any previously identified isoforms.

    Funded by: NHLBI NIH HHS: HL28573

    Proceedings of the National Academy of Sciences of the United States of America 1987;84;12;4039-43

Gene lists (9)

Gene List Source Species Name Description Gene count
L00000009 G2C Homo sapiens Human PSD Human orthologues of mouse PSD adapted from Collins et al (2006) 1080
L00000011 G2C Homo sapiens Human clathrin Human orthologues of mouse clathrin coated vesicle genes adapted from Collins et al (2006) 150
L00000012 G2C Homo sapiens Human Synaptosome Human orthologues of mouse synaptosome adapted from Collins et al (2006) 152
L00000013 G2C Homo sapiens Human mGluR5 Human orthologues of mouse mGluR5 complex adapted from Collins et al (2006) 52
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000059 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-CONSENSUS Human cortex PSD consensus 748
L00000061 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-CONSENSUS Mouse cortex PSD consensus (ortho) 984
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
L00000071 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list (ortho) 1556
© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

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