G2Cdb::Gene report

Gene id
G00001796
Gene symbol
MAP2 (HGNC)
Species
Homo sapiens
Description
microtubule-associated protein 2
Orthologue
G00000547 (Mus musculus)

Databases (8)

Gene
ENSG00000078018 (Ensembl human gene)
4133 (Entrez Gene)
47 (G2Cdb plasticity & disease)
MAP2 (GeneCards)
Literature
157130 (OMIM)
Marker Symbol
HGNC:6839 (HGNC)
Protein Expression
1984 (human protein atlas)
Protein Sequence
P11137 (UniProt)

Synonyms (3)

  • MAP2A
  • MAP2B
  • MAP2C

Diseases (2)

Disease Nervous effect Mutations Found Literature Mutations Type Genetic association?
D00000177: Autism Y Y (14986829) Deletion (D) ?
D00000178: Rett syndrome Y Y (14986829) Deletion (D) ?

References

  • Chromosome 2 deletion encompassing the MAP2 gene in a patient with autism and Rett-like features.

    Pescucci C, Meloni I, Bruttini M, Ariani F, Longo I, Mari F, Canitano R, Hayek G, Zappella M and Renieri A

    Medical Genetics, Department of Molecular Biology, University of Siena, Siena, Italy.

    We present here a unique case of a 14-year-old female with autism and some features similar to Rett syndrome (RTT). Genetic analysis demonstrated a large deletion of chromosome 2q instead of a MECP2 mutation. Like a Rett patient, she is dyspraxic and shows frequent hand-washing stereotypic activities, hyperpnea, and bruxism. Like a preserved speech variant (PSV) of RTT, she is obese, able to speak in second and third persons, frequently echolalic, and has final normal head circumference and autistic behavior. In addition, she has dysmorphic features such as down-slanting palpebral fissures, low set ears without lobuli, bilateral flat feet, and bilateral syndactyly of the second and third toes, which do not belong to the Rett spectrum. She has a de novo chromosomal deletion in 2q34 of paternal origin. Gene content analysis of the deleted region showed the presence of 47 genes (14 putative and 33 known genes). This region contains some interesting genes such as ADAM23/MDC3, CREB1, KLF7, and MAP2. Because alteration of neuronal maturation, dendritic anomalies, and a decrease in MAP2 immunoreactivity in white matter neurons are well documented in RTT patients, we propose MAP2 gene as a good candidate for the generation of PSV phenotype in this case.

    Funded by: Telethon: GGP02372, GTF02006

    Clinical genetics 2003;64;6;497-501

Literature (62)

Pubmed - human_disease

  • Chromosome 2 deletion encompassing the MAP2 gene in a patient with autism and Rett-like features.

    Pescucci C, Meloni I, Bruttini M, Ariani F, Longo I, Mari F, Canitano R, Hayek G, Zappella M and Renieri A

    Medical Genetics, Department of Molecular Biology, University of Siena, Siena, Italy.

    We present here a unique case of a 14-year-old female with autism and some features similar to Rett syndrome (RTT). Genetic analysis demonstrated a large deletion of chromosome 2q instead of a MECP2 mutation. Like a Rett patient, she is dyspraxic and shows frequent hand-washing stereotypic activities, hyperpnea, and bruxism. Like a preserved speech variant (PSV) of RTT, she is obese, able to speak in second and third persons, frequently echolalic, and has final normal head circumference and autistic behavior. In addition, she has dysmorphic features such as down-slanting palpebral fissures, low set ears without lobuli, bilateral flat feet, and bilateral syndactyly of the second and third toes, which do not belong to the Rett spectrum. She has a de novo chromosomal deletion in 2q34 of paternal origin. Gene content analysis of the deleted region showed the presence of 47 genes (14 putative and 33 known genes). This region contains some interesting genes such as ADAM23/MDC3, CREB1, KLF7, and MAP2. Because alteration of neuronal maturation, dendritic anomalies, and a decrease in MAP2 immunoreactivity in white matter neurons are well documented in RTT patients, we propose MAP2 gene as a good candidate for the generation of PSV phenotype in this case.

    Funded by: Telethon: GGP02372, GTF02006

    Clinical genetics 2003;64;6;497-501

Pubmed - other

  • Oncogenic BRAFV600E induces expression of neuronal differentiation marker MAP2 in melanoma cells by promoter demethylation and down-regulation of transcription repressor HES1.

    Maddodi N, Bhat KM, Devi S, Zhang SC and Setaluri V

    Department of Dermatology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA.

    MAP2 is a neuron-specific microtubule-associated protein that binds and stabilizes dendritic microtubules. Previously, we showed that MAP2 expression is (a) activated in cutaneous primary melanoma and (b) inversely associated with melanoma tumor progression. We also showed that ectopic expression of MAP2 in metastatic melanoma cells inhibits cell growth by inducing mitotic spindle defects and apoptosis. However, molecular mechanisms of regulation of MAP2 gene expression in melanoma are not understood. Here, we show that in melanoma cells MAP2 expression is induced by the demethylating agent 5-aza-2'-cytidine, and MAP2 promoter is progressively methylated during melanoma progression, indicating that epigenetic mechanisms are involved in silencing of MAP2 in melanoma. In support of this, methylation of MAP2 promoter DNA in vitro inhibits its activity. Because MAP2 promoter activity levels in melanoma cell lines also correlated with activating mutation in BRAF, a gene that is highly expressed in neurons, we hypothesized that BRAF signaling is involved in MAP2 expression. We show that hyperactivation of BRAF-MEK signaling activates MAP2 expression in melanoma cells by two independent mechanisms, promoter demethylation or down-regulation of neuronal transcription repressor HES1. Our data suggest that BRAF oncogene levels can regulate melanoma neuronal differentiation and tumor progression.

    Funded by: NCI NIH HHS: R21 CA125091, R21CA125091; NINDS NIH HHS: R01 NS045926, R01NS045926

    The Journal of biological chemistry 2010;285;1;242-54

  • Microtubule-associated protein-2 is a sensitive marker of primary and metastatic neuroblastoma.

    Krishnan C, Higgins JP, West RB, Natkunam Y, Heerema-McKenney A and Arber DA

    Department of Pathology, Stanford University, Stanford, CA 94205, USA. Chandra.krishnan@yahoo.com

    Background: Microtubule-associated protein-2 (MAP-2) is a protein expressed in high levels in cells derived from the neural crest. To the best of our knowledge, MAP-2 expression has not been thoroughly evaluated in tissues outside of the central nervous tissue. We examined the diagnostic utility of MAP-2 as a marker of neuroblastoma and attempted to characterize the expression of this protein in other tumors in the morphologic differential diagnosis of neuroblastoma.

    Results: MAP-2 showed significant cytoplasmic reactivity in 95% of primary and 100% of metastatic neuroblastomas. Included within this set of tumors were 3 undifferentiated neuroblastomas, all of which showed strong staining. MAP-2 did not show significant staining in the majority of other small round blue cell tumors within the morphologic differential. Additionally, MAP-2 showed comparable sensitivity in staining primary neuroblastomas as compared with synaptophysin, chromogranin, CD56, and beta-catenin. In contrast to other markers of neuroblastoma, MAP-2 did not show significant cross reactivity to native bone marrow precursors, thus eliminating a potential source of confusion. In normal tissues, MAP-2 staining was essentially restricted to organs derived from the neural crest (adrenal medulla, endocrine organs). Variant patterns of staining were seen in exocrine organs, monocyte/macrophages and solitary fibrous tumor/hemangiopericytoma family of tumors. Rarely, high-grade adult sarcomas exhibiting strong cytoplasmic MAP-2 staining were seen.

    Conclusions: MAP-2 is a sensitive and specific marker of neuroblastoma, both in the primary tumor and bone marrow biopsy settings. We think that MAP-2, in conjunction with synaptophysin, is a very powerful immunohistochemical marker in differentiating neuroblastoma from its morphologic mimics.

    The American journal of surgical pathology 2009;33;11;1695-704

  • Differential expression of microtubule-associated protein 2 in melanocytic skin lesions.

    Gambichler T, Rotterdam S, Radkowski K, Altmeyer P and Kreuter A

    Department of Dermatology and Allergology, Ruhr-University Bochum, Gudrunstrasse 56, D-44791 Bochum, Germany.

    Neoplastic melanocytes may exhibit certain differentiation characteristics of other neural-crest derivatives. We aimed to study the expression of microtubule-associated protein 2 (MAP-2) in different types of melanocytic skin lesions. Paraffin-embedded sections of 42 benign nevi (BN), 22 dysplastic nevi (DN), 45 superficial spreading melanomas (SSMs), and 15 subcutaneous melanoma metastases were immunohistologically assessed using the monoclonal mouse MAP-2ab antibody (Zytomed, Berlin, Germany). The percentage MAP-2 expression of DN and SSMs was significantly increased compared with BN. Moreover, subcutaneous melanoma metastases showed significantly decreased MAP-2 expression compared with DN and SSMs. In SSMs, MAP-2 expression significantly correlated with the Breslow vertical tumor thickness, Clark level, and stage of disease. We observed that MAP-2 is differentially expressed during the development and progression of benign and malignant melanocytic skin lesions. In contrast with the findings of previous studies, our data indicate that MAP-2 is a moderately positive predictor of the progression of SSMs.

    American journal of clinical pathology 2009;131;5;710-4

  • Prefrontal cortex shotgun proteome analysis reveals altered calcium homeostasis and immune system imbalance in schizophrenia.

    Martins-de-Souza D, Gattaz WF, Schmitt A, Rewerts C, Maccarrone G, Dias-Neto E and Turck CW

    Laboratório de Neurociências, Instituto de Psiquiatria, Universidade de São Paulo, Rua. Dr. Ovidio Pires de Campos, no 785, Consolação, São Paulo, SP 05403-010, Brazil.

    Schizophrenia is a complex disease, likely to be caused by a combination of serial alterations in a number of genes and environmental factors. The dorsolateral prefrontal cortex (Brodmann's Area 46) is involved in schizophrenia and executes high-level functions such as working memory, differentiation of conflicting thoughts, determination of right and wrong concepts and attitudes, correct social behavior and personality expression. Global proteomic analysis of post-mortem dorsolateral prefrontal cortex samples from schizophrenia patients and non-schizophrenic individuals was performed using stable isotope labeling and shotgun proteomics. The analysis resulted in the identification of 1,261 proteins, 84 of which showed statistically significant differential expression, reinforcing previous data supporting the involvement of the immune system, calcium homeostasis, cytoskeleton assembly, and energy metabolism in schizophrenia. In addition a number of new potential markers were found that may contribute to the understanding of the pathogenesis of this complex disease.

    European archives of psychiatry and clinical neuroscience 2009;259;3;151-63

  • Hypoxic-ischemic changes in SIDS brains as demonstrated by a reduction in MAP2-reactive neurons.

    Oehmichen M, Woetzel F and Meissner C

    Institute of Legal Medicine of Schleswig Holstein, Lübeck, Germany. moehmichen@gmx.de

    Sudden infant death syndrome (SIDS) is characterized by a lack of any known morphological or functional organ changes that could explain the lethal process. In the present study we investigated the hypothesis of an association between hypoxic/ischemic injury and SIDS deaths. In a previous study, we could demonstrate by quantitative immunohistochemistry a distinct drop in microtubule-associated protein (MAP2) reactivity in neurons of adult, human brains secondary to acute hypoxic-ischemic injuries. Here we applied the same method on sections of the frontal cortex and hippocampus of 41 brains of infants younger than 1 year of age. For each brain area 100 selected neurons were evaluated for their MAP2 reactivity in the different layers of the frontal cortex and in the different segments of the hippocampus. Three groups were compared: (1) SIDS victims (n = 17), (2) infants with hypoxia/ischemia (control group one; n = 14), (3) infants without hypoxic/ischemic injury (control group two; n = 10). The SIDS group and hypoxic/ischemic group exhibited a general reduction in the number of MAP2 reactive neurons in comparison with the non-hypoxic/ischemic injury group. The SIDS group also had a significantly lower (P < 0.05) number of reactive neurons in the CA2 and CA3 areas of the hippocampus than did control group two. No difference was detected between the SIDS group and control group one. The SIDS brains were thus found to display hypoxic/ischemic features without however providing evidence as to the cause of the oxygen reduction.

    Acta neuropathologica 2009;117;3;267-74

  • MAP-2 immunoexpression in gliomatosis cerebri.

    Romeike BF and Mawrin C

    Histopathology 2009;54;4;504-5

  • Involvement of microtubule-associated protein 2 (MAP2) in oral cancer cell motility: a novel biological function of MAP2 in non-neuronal cells.

    Liu SY, Chen YT, Tseng MY, Hung CC, Chiang WF, Chen HR, Shieh TY, Chen CH, Jou YS and Chen JY

    Department of Oral and Maxillofacial Surgery, Chi-Mei Medical Center, Tainan, Taiwan.

    Microtubule-associated protein 2 (MAP2) has been better known for its well-defined role primarily in neurite outgrowth during neuronal development. However, the biological functions of MAP2 in non-neuronal cells, such as epithelial cells, remain largely unknown. In the present study, we sought to investigate the cellular functions of MAP2 by separately establishing stable expression of two MAP2 isoforms, MAP2A and MAP2C, in oral squamous cell carcinoma, Ca9-22. Ectopic expression of MAP2A or MAP2C results in microtubule bundling predominantly at the cell periphery. Remarkably, overexpression of MAP2A but not MAP2C significantly promotes migration of Ca9-22 cells, whereas knockdown of MAP2A expression by specific siRNA oligos dramatically decreases cell migration of HaCaT, an immortalized keratinocyte cell line with abundant endogenous MAP2A. Furthermore, by immunohistochemical studies, MAP2A was shown to highly and selectively express 1db5 in invasive oral cancer tissues, consistent with its motility-promoting cellular function revealed through in vitro assays. Thus, our findings have not only identified a novel role of MAP2 in non-neuronal cells, but also provided the first implication of MAP2 in malignant oral cancer tissues.

    Biochemical and biophysical research communications 2008;366;2

  • Analysis of the weak interactions of ADP-Unc104 and ADP-kinesin with microtubules and their inhibition by MAP2c.

    Al-Bassam J, Roger B, Halpain S and Milligan RA

    Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.

    Microtubule based motors like conventional kinesin (Kinesin-1) and Unc104 (Kinesin-3), and classical microtubule associated proteins (MAPs), including MAP2, are intimately involved in neurite formation and organelle transport. The processive motility of both these kinesins involves weak microtubule interactions in the ADP-bound states. Using cosedimentation assays, we have investigated these weak interactions and characterized their inhibition by MAP2c. We show that Unc104 binds microtubules with five-fold weaker affinity and two-fold higher stoichiometry compared with conventional kinesin. Unc104 and conventional kinesin binding affinities are primarily dependent on positively charged residues in the Unc104 K-loop and conventional kinesin neck coiled-coil and removal of these residues affects Unc104 and conventional kinesin differently. We observed that MAP2c acts primarily as a competitive inhibitor of Unc104 but a mixed inhibitor of conventional kinesin. Our data suggest a specific model in which MAP2c differentially interferes with each kinesin motor by inhibiting its weak attachment to the tubulin C-termini. This is reminiscent of the defects we have observed in Unc104 and kinesin mutants in which the positively charged residues in K-loop and neck coiled-coil domains were removed.

    Funded by: NIGMS NIH HHS: GM52468; NIMH NIH HHS: MH50861, R01 MH050861

    Cell motility and the cytoskeleton 2007;64;5;377-89

  • Global, in vivo, and site-specific phosphorylation dynamics in signaling networks.

    Olsen JV, Blagoev B, Gnad F, Macek B, Kumar C, Mortensen P and Mann M

    Center for Experimental BioInformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark.

    Cell signaling mechanisms often transmit information via posttranslational protein modifications, most importantly reversible protein phosphorylation. Here we develop and apply a general mass spectrometric technology for identification and quantitation of phosphorylation sites as a function of stimulus, time, and subcellular location. We have detected 6,600 phosphorylation sites on 2,244 proteins and have determined their temporal dynamics after stimulating HeLa cells with epidermal growth factor (EGF) and recorded them in the Phosida database. Fourteen percent of phosphorylation sites are modulated at least 2-fold by EGF, and these were classified by their temporal profiles. Surprisingly, a majority of proteins contain multiple phosphorylation sites showing different kinetics, suggesting that they serve as platforms for integrating signals. In addition to protein kinase cascades, the targets of reversible phosphorylation include ubiquitin ligases, guanine nucleotide exchange factors, and at least 46 different transcriptional regulators. The dynamic phosphoproteome provides a missing link in a global, integrative view of cellular regulation.

    Cell 2006;127;3;635-48

  • Tubulin-mediated binding of human immunodeficiency virus-1 Tat to the cytoskeleton causes proteasomal-dependent degradation of microtubule-associated protein 2 and neuronal damage.

    Aprea S, Del Valle L, Mameli G, Sawaya BE, Khalili K and Peruzzi F

    Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania 19122, USA.

    One of the hallmarks of human immunodeficiency virus (HIV)-1 associated pathology in the CNS is deterioration of neuronal processes. Although there is mounting evidence of neuronal toxicity and cell death induced by the HIV-1 transactivating factor Tat, the molecular events linked directly to its detrimental effect on neuronal cells remain unclear. In this study, we used rat embryonic cortical neurons and demonstrated that Tat causes rapid degradation of microtubule-associated protein 2 (MAP2) and the collapse of cytoskeletal filaments. The mechanism of Tat action on MAP2 stability involved Tat-mediated translocation of the proteasome to the site of microtubule filaments. Immunohistochemical analysis of clinical samples from patients with HIV encephalopathy further revealed a significant decrease in MAP2 with predominant cytoplasmic 20S in cortical neurons near microglial nodules. These findings indicate a novel mechanism for the action of Tat on neuronal cells. It involves proteasome-mediated MAP2 degradation and may account for the loss of MAP2 and neuronal damage observed in the brain of AIDS patients with neurological dysfunctions.

    The Journal of neuroscience : the official journal of the Society for Neuroscience 2006;26;15;4054-62

  • Transcriptional regulation of human MAP2 gene in melanoma: role of neuronal bHLH factors and Notch1 signaling.

    Bhat KM, Maddodi N, Shashikant C and Setaluri V

    Department of Dermatology, University of Wisconsin, 1300 University Avenue, B25, Madison, WI 53706, USA.

    Microtubule-associated protein 2 (MAP2), a neuron-specific protein, stabilizes microtubules and is critical for neurite outgrowth and dendrite development. Although MAP2 is widely used as a marker of neuronal differentiation, regulation of its transcription has not been investigated. We showed that MAP2 is frequently activated in human cutaneous melanoma. Here, we identified a 2.2 kb region that is sufficient for neuronal-specific expression in vitro and in vivo. Comparative analysis of the mouse, rat and human MAP2 promoter sequences showed the presence of a conserved bHLH factor binding sites. Electrophoretic mobility shift analysis, promoter mutagenesis and co-transfection experiments showed that NeuroD, a pro-neuronal differentiation factor, and Hairy and Enhancer of Split (HES1), a transcription repressor, are involved in the regulation of MAP2 promoter activity. Melanoma cells express both NeuroD and HES1. Chromatin immunoprecipitation showed that in metastatic melanoma cells N-box region of the MAP2 promoter is occupied by endogenous HES1. We show that the inhibition of Notch signaling, a regulator of HES1 gene expression, and/or shRNA knockdown of HES1 results in the upregulation of MAP2 promoter activity. Thus, our data suggest that Notch signaling, which is implicated in melanoma progression, and HES1 play a role in MAP2 gene regulation during melanoma progression.

    Nucleic acids research 2006;34;13;3819-32

  • Disruption of the actin network enhances MAP-2c and Fyn-induced process outgrowth.

    Zamora-Leon SP and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

    We investigated the interaction of MAP-2c and Fyn in the initiation of process outgrowth in COS7 cells. Single transfections of Fyn and MAP-2c resulted in a dramatic decrease in flat, rounded COS7 cells, and a significant increase in both the number of cells with multiple short, spike-like processes, and cells with longer processes. Co-transfection of Fyn and MAP-2c resulted in an additive increase in the number of cells with more than two processes and discrete sites of co-localization within processes. When single or double transfected cells were treated with cytochalasin D or lantrunculin there was a dramatic increase in the number of cells with more than two processes. In addition, there was an increase in the length of the processes, both in single and double transfected cells, suggesting that the actin meshwork provides a barrier for MT-based process extension. When co-transfected cells were post-treated with nocodazole, Fyn was not associated with MAP-2c and acetylated, stable tubulin. Although some Fyn/MAP-2c co-localization was retained, punctate staining of MAP-2c and Fyn were observed at the cell periphery, in areas devoid of stable MTs. Mutations in either tyrosine 67 (Tyr67), a site on human MAP-2c phosphorylated by Fyn, or a second tyrosine residue (Tyr50), did not alter the ability of MAP-2c and Fyn to induce process outgrowth. These studies suggest that independent of one another MAP-2c and Fyn are able to induce process outgrowth and in concert can initiate and enhance process outgrowth in an additive manner.

    Cell motility and the cytoskeleton 2005;62;2;110-23

  • Interaction of microtubule-associated protein-2 and p63: a new link between microtubules and rough endoplasmic reticulum membranes in neurons.

    Farah CA, Liazoghli D, Perreault S, Desjardins M, Guimont A, Anton A, Lauzon M, Kreibich G, Paiement J and Leclerc N

    Département de Pathologie et Biologie Cellulaire, Université de Montréal, CP 6128, Succ. Centre-ville, Montréal, Québec H3C 3J7, Canada.

    Neurons are polarized cells presenting two distinct compartments, dendrites and an axon. Dendrites can be distinguished from the axon by the presence of rough endoplasmic reticulum (RER). The mechanism by which the structure and distribution of the RER is maintained in these cells is poorly understood. In the present study, we investigated the role of the dendritic microtubule-associated protein-2 (MAP2) in the RER membrane positioning by comparing their distribution in brain subcellular fractions and in primary hippocampal cells and by examining the MAP2-microtubule interaction with RER membranes in vitro. Subcellular fractionation of rat brain revealed a high MAP2 content in a subfraction enriched with the endoplasmic reticulum markers ribophorin and p63. Electron microscope morphometry confirmed the enrichment of this subfraction with RER membranes. In cultured hippocampal neurons, MAP2 and p63 were found to concomitantly compartmentalize to the dendritic processes during neuronal differentiation. Protein blot overlays using purified MAP2c protein revealed its interaction with p63, and immunoprecipitation experiments performed in HeLa cells showed that this interaction involves the projection domain of MAP2. In an in vitro reconstitution assay, MAP2-containing microtubules were observed to bind to RER membranes in contrast to microtubules containing tau, the axonal MAP. This binding of MAP2c microtubules was reduced when an anti-p63 antibody was added to the assay. The present results suggest that MAP2 is involved in the association of RER membranes with microtubules and thereby could participate in the differential distribution of RER membranes within a neuron.

    The Journal of biological chemistry 2005;280;10;9439-49

  • Phosphoproteomic analysis of synaptosomes from human cerebral cortex.

    DeGiorgis JA, Jaffe H, Moreira JE, Carlotti CG, Leite JP, Pant HC and Dosemeci A

    Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.

    Protein phosphorylation is a crucial post-translational modification mechanism in the regulation of synaptic organization and function. Here, we analyzed synaptosome fractions from human cerebral cortex obtained during therapeutic surgery. To minimize changes in the phosphorylation state of proteins, the tissue was homogenized within two minutes of excision. Synaptosomal proteins were digested with trypsin and phosphopeptides were isolated by immobilized metal affinity chromatography and analyzed by liquid chromatography and tandem mass spectrometry. The method allowed the detection of residues on synaptic proteins that were presumably phosphorylated in the intact cell, including synapsin 1, syntaxin 1, and SNIP, PSD-93, NCAM, GABA-B receptor, chaperone molecules, and protein kinases. Some of the residues identified are the same or homologous to sites that had been previously described to be phosphorylated in mammals whereas others appear to be novel sites which, to our knowledge, have not been reported previously. The study shows that new phosphoproteomic strategies can be used to analyze subcellular fractions from small amounts of tissue for the identification of phosphorylated residues for research and potentially for diagnostic purposes.

    Journal of proteome research 2005;4;2;306-15

  • Fyn phosphorylates human MAP-2c on tyrosine 67.

    Zamora-Leon SP, Bresnick A, Backer JM and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

    The Src homology 3 (SH3) domain of Fyn binds to a conserved PXXP motif on microtubule-associated protein-2. Co-transfections into COS7 cells and in vitro kinase assays performed with Fyn and wild-type, or mutant MAP-2c, determined that Fyn phosphorylated MAP-2c on tyrosine 67. The phosphorylation generated a consensus sequence for the binding of the SH2 domain of Grb2 (pYSN). Pull-down assays with SH2-Grb2 from human fetal brain homogenates, and co-immunoprecipitation of Grb2 and MAP-2 confirmed the interaction in vivo, and demonstrated that MAP-2c is tyrosine-phosphorylated in human fetal brain. Filter overlay assays confirmed that the SH2 domain of Grb2 binds to human MAP-2c following incubation with active Fyn. Enzyme-linked immunosorbent assays confirmed the interaction between the SH2 domain of Grb2 and a tyrosine-phosphorylated MAP-2 peptide spanning the pY(67)SN motif. Thus, MAP-2c can directly recruit multiple signaling proteins important for central nervous system development.

    Funded by: NIGMS NIH HHS: GM55692; NINDS NIH HHS: NS38102

    The Journal of biological chemistry 2005;280;3;1962-70

  • MAP-2 expression in the human adenohypophysis and in pituitary adenomas. An immunohistochemical study.

    Rotondo F, Oniya K, Kovacs K, Bell CD and Scheithauer BW

    Department of Laboratory Medicine, Division of Pathology, St. Michael's Hospital, Toronto, ON, Canada. rotondof@smh.toronto.on.ca

    MAP-2, a well characterized member of the microtubule associated protein (MAP) family, binds to and stabilizes microtubules and is involved in cell proliferation as well as neuronal differentiation. The aim of the present work was to study MAP-2 expression in human adenohypophyses and pituitary adenomas. To our knowledge, data regarding MAP-2 expression in human pituitaries has not been reported to date. For immunohistochemistry, the streptavidin-biotin-peroxidase complex method was used. Nine non-tumorous adenohypophyses and 77 adenomas (GH-, PRL-, ACTH-, TSH-, FSH/LH- and/or alpha subunit- producing or immunonegative tumors) were investigated. The results show that MAP-2 is expressed in the cytoplasm of non-tumorous adenohypophysial cells as well as of various pituitary adenoma types. No significant correlation was found between MAP-2 expression and gender, patient age, mitotic activity, MIB-1 labelling indices, hormone immunoprofile, and endocrine status, ie. hormonal activity or lack thereof. Thus MAP-2 expression cannot be used to estimate cell proliferation rate, growth potential, endocrine activity or biologic behaviour of an adenoma. Immunopositivity appeared to be stronger in the cytoplasm of adenoma cells than in that of non-tumorous adenohypophysial cells, implying that the adenoma cells contain larger quantities of MAP-2. It can be concluded that the functional activity of MAP-2 is not associated with the manufacture of any specific adenohypophysial hormone(s) and is not limited to one specific cell type.

    Pituitary 2005;8;2;75-9

  • Phosphoproteomic analysis of the developing mouse brain.

    Ballif BA, Villén J, Beausoleil SA, Schwartz D and Gygi SP

    Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.

    Proper development of the mammalian brain requires the precise integration of numerous temporally and spatially regulated stimuli. Many of these signals transduce their cues via the reversible phosphorylation of downstream effector molecules. Neuronal stimuli acting in concert have the potential of generating enormous arrays of regulatory phosphoproteins. Toward the global profiling of phosphoproteins in the developing brain, we report here the use of a mass spectrometry-based methodology permitting the first proteomic-scale phosphorylation site analysis of primary animal tissue, identifying over 500 protein phosphorylation sites in the developing mouse brain.

    Funded by: NHGRI NIH HHS: HG00041

    Molecular & cellular proteomics : MCP 2004;3;11;1093-101

  • Reduced spinophilin but not microtubule-associated protein 2 expression in the hippocampal formation in schizophrenia and mood disorders: molecular evidence for a pathology of dendritic spines.

    Law AJ, Weickert CS, Hyde TM, Kleinman JE and Harrison PJ

    University Department of Psychiatry, Neurosciences Building, Warneford Hospital, Oxford OX3 7JX, UK. amanda.law@psych.ox.ac.uk.

    Objective: Aberrant synaptic connectivity may underlie the involvement of the hippocampus in schizophrenia. There is reasonable neuropathological evidence for a presynaptic pathology but few studies of the postsynaptic component. This study tested the hypothesis that hippocampal dendritic pathology is also present in schizophrenia.

    Method: Using in situ hybridization in sections of hippocampal formation from 10 patients with schizophrenia, 10 patients with mood disorders (three with bipolar disorder and seven with major depression), and 10 healthy comparison subjects, the authors examined the expression of two important dendritic genes: spinophilin, which serves as a marker of dendritic spines, and microtubule-associated protein 2 (MAP2), an overall dendritic marker.

    Results: The patients with schizophrenia had lower levels of spinophilin mRNA in CA4 (hilus), CA3, the subiculum, and the entorhinal cortex than did the normal comparison subjects. The mood disorder group showed similar differences from the comparison group. MAP2 and cyclophilin mRNA did not differ between the groups in any subfield.

    Conclusions: Decreased spinophilin but unchanged MAP2 expression provides molecular evidence for a hippocampal dendritic pathology in schizophrenia that preferentially affects the spines. As spines are the target of most glutamatergic synapses, the data extend the evidence that excitatory synapses are particularly affected. Similar dendritic spine pathology may also occur in mood disorders.

    The American journal of psychiatry 2004;161;10;1848-55

  • Microtubule-associated protein-2 immunoreactivity: a useful tool in the differential diagnosis of low-grade neuroepithelial tumors.

    Blümcke I, Müller S, Buslei R, Riederer BM and Wiestler OD

    Department of Neuropathology, University of Erlangen-Nuremberg, 91054, Erlangen, Germany. ingmar.bluemcke@neuropatho.med.uni-erlangen.de

    Complex and variable morphological phenotypes pose a major challenge to the histopathological classification of neuroepithelial tumors. This applies in particular for low-grade gliomas and glio-neuronal tumors. Recently, we and others have identified microtubule-associated protein-2 (MAP2) as an immunohistochemical marker expressed in the majority of glial tumors. Characteristic cell morphologies can be recognized by MAP2 immunoreactivity in different glioma entities, i.e., process sparse oligodendroglial versus densely ramified astrocytic elements. Here, we describe MAP2-immunoreactivity patterns in a large series of various neuroepithelial tumors and related neoplasms (n = 960). Immunohistochemical analysis led to the following conclusions: (1) specific pattern of MAP2-positive tumor cells can be identified in 95% of glial neoplasms; (2) ependymal tumors do not express MAP2 in their rosette-forming cell component; (3) tumors of the pineal gland as well as malignant embryonic tumors are also characterized by abundant MAP2 immunoreactivity; (4) virtually no MAP2 expression can be observed in the neoplastic glial component of glio-neuronal tumors, i.e. gangliogliomas; (5) malignant glial tumor variants (WHO grade III or IV) exhibit different and less specific MAP2 staining patterns compared to their benign counterparts (WHO grade I or II); (6) with the exception of melanomas and small cell lung cancers, MAP2 expression is very rare in metastatic and non-neuroepithelial tumors; (7) glial MAP2 expression was not detected in 56 non-neoplastic lesions. These data point towards MAP2 as valuable diagnostic tool for pattern recognition and differential diagnosis of low-grade neuroepithelial tumors.

    Acta neuropathologica 2004;108;2;89-96

  • Antioxidant protection from HIV-1 gp120-induced neuroglial toxicity.

    Walsh KA, Megyesi JF, Wilson JX, Crukley J, Laubach VE and Hammond RR

    Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada. rhammond@uwo.ca

    BACKGROUND: The pathogenesis of HIV-1 glycoprotein 120 (gp120) associated neuroglial toxicity remains unresolved, but oxidative injury has been widely implicated as a contributing factor. In previous studies, exposure of primary human central nervous system tissue cultures to gp120 led to a simplification of neuronal dendritic elements as well as astrocytic hypertrophy and hyperplasia; neuropathological features of HIV-1-associated dementia. Gp120 and proinflammatory cytokines upregulate inducible nitric oxide synthase (iNOS), an important source of nitric oxide (NO) and nitrosative stress. Because ascorbate scavenges reactive nitrogen and oxygen species, we studied the effect of ascorbate supplementation on iNOS expression as well as the neuronal and glial structural changes associated with gp120 exposure. METHODS: Human CNS cultures were derived from 16-18 week gestation post-mortem fetal brain. Cultures were incubated with 400 microM ascorbate-2-O-phosphate (Asc-p) or vehicle for 18 hours then exposed to 1 nM gp120 for 24 hours. The expression of iNOS and neuronal (MAP2) and astrocytic (GFAP) structural proteins was examined by immunohistochemistry and immunofluorescence using confocal scanning laser microscopy (CSLM). RESULTS: Following gp120 exposure iNOS was markedly upregulated from undetectable levels at baseline. Double label CSLM studies revealed astrocytes to be the prime source of iNOS with rare neurons expressing iNOS. This upregulation was attenuated by the preincubation with Asc-p, which raised the intracellular concentration of ascorbate. Astrocytic hypertrophy and neuronal injury caused by gp120 were also prevented by preincubation with ascorbate. CONCLUSIONS: Ascorbate supplementation prevents the deleterious upregulation of iNOS and associated neuronal and astrocytic protein expression and structural changes caused by gp120 in human brain cell cultures.

    Journal of neuroinflammation 2004;1;1;8

  • Human CNS cultures exposed to HIV-1 gp120 reproduce dendritic injuries of HIV-1-associated dementia.

    Iskander S, Walsh KA and Hammond RR

    Department of Pathology, London Health Sciences Centre, University of Western Ontario, London, ON, Canada. rhammond@uwo.ca

    HIV-1-associated dementia remains a common subacute to chronic central nervous system degeneration in adult and pediatric HIV-1 infected populations. A number of viral and host factors have been implicated including the HIV-1 120 kDa envelope glycoprotein (gp120). In human post-mortem studies using confocal scanning laser microscopy for microtubule-associated protein 2 and synaptophysin, neuronal dendritic pathology correlated with dementia. In the present study, primary human CNS cultures exposed to HIV-1 gp120 at 4 weeks in vitro suffered gliosis and dendritic damage analogous to that described in association with HIV-1-associated dementia.

    Journal of neuroinflammation 2004;1;1;7

  • MARK4 is a novel microtubule-associated proteins/microtubule affinity-regulating kinase that binds to the cellular microtubule network and to centrosomes.

    Trinczek B, Brajenovic M, Ebneth A and Drewes G

    Department of Medicinal Chemistry, University of Kansas, Malott Hall, Lawrence, Kansas 66045, USA.

    The MARK protein kinases were originally identified by their ability to phosphorylate a serine motif in the microtubule-binding domain of tau that is critical for microtubule binding. Here, we report the cloning and expression of a novel human paralog, MARK4, which shares 75% overall homology with MARK1-3 and is predominantly expressed in brain. Homology is most pronounced in the catalytic domain (90%), and MARK4 readily phosphorylates tau and the related microtubule-associated protein 2 (MAP2) and MAP4. In contrast to the three paralogs that all exhibit uniform cytoplasmic localization, MARK4 colocalizes with the centrosome and with microtubules in cultured cells. Overexpression of MARK4 causes thinning out of the microtubule network, concomitant with a reorganization of microtubules into bundles. In line with these findings, we show that a tandem affinity-purified MARK4 protein complex contains alpha-, beta-, and gamma-tubulin. In differentiated neuroblastoma cells, MARK4 is localized prominently at the tips of neurite-like processes. We suggest that although the four MARK/PAR-1 kinases might play multiple cellular roles in concert with different targets, MARK4 is likely to be directly involved in microtubule organization in neuronal cells and may contribute to the pathological phosphorylation of tau in Alzheimer's disease.

    The Journal of biological chemistry 2004;279;7;5915-23

  • Specific induction of the high-molecular-weight microtubule-associated protein 2 (hmw-MAP2) by betel quid extract in cultured oral keratinocytes: clinical implications in betel quid-associated oral squamous cell carcinoma (OSCC).

    Chen JY, Chang YL, Yu YC, Chao CC, Kao HW, Wu CT, Lin WC, Ko JY and Jou YS

    Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.

    Betel quid (BQ) chewing, a popular habit in numerous Asian countries including India and Taiwan, has a strong correlation with an increased risk of oral squamous cell carcinoma (OSCC). While substantial efforts have been made to test the cytotoxic, genotoxic and mutagenic effects of BQ extract and its components, the disease mechanisms underlying BQ-induced oral carcinogenesis remain obscure. Here, we show that a neuronal protein, microtubule-associated protein 2 (MAP2), was induced by BQ extract in cultured normal human oral keratinocytes (NHOKs). Subsequent analyses demonstrated that such induction was more eminent and consistent in the high-molecular-weight isoform of MAP2 (hmw-MAP2) than that in its low-molecular-weight counterpart (lmw-MAP2). Furthermore, we analyzed expression of hmw-MAP2 protein in 88 oral specimens consisting of clinicopathologically pre-malignant (leukoplakia) and malignant (OSCC) lesions, along with their adjacent normal mucosa. Immunohistochemistry revealed that, with the exposure to BQ, the hmw-MAP2 was over-expressed in 41.2% (7/17) of OSCC, 11.2% (1/9) of leukoplakia and none (0/19) of normal mucosa. In contrast, expression of the hmw-MAP2 was barely detected in BQ-free OSCC. These results suggest a significant correlation between expression of the hmw-MAP2 and BQ-associated progression of oral carcinogenesis (P=0.0046). Interestingly, the hmw-MAP2 was found to preferentially express in histopathologically less differentiated OSCC (P=0.014); the percentages of positive staining in poorly, moderately and well differentiated OSCC were 62.5, 21.4 and 7.1%, respectively. However, BQ chewing appeared to have marginal correlation with such propensity. Finally, we show that the majority of hmw-MAP2-positive poorly differentiated lesions were also histopathologically invasive. Taken together, these findings suggest the possibility that the hmw-MAP2 may be a diagnostic marker for BQ-chewing lesions and a potential therapeutic target. To our knowledge, this study has provided the first clinical implication that closely links a cytoskeletal protein to BQ-associated oral cancer.

    Carcinogenesis 2004;25;2;269-76

  • 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

  • An unappreciated role for RNA surveillance.

    Hillman RT, Green RE and Brenner SE

    Department of Bioengineering, University of California, Berkeley, CA 94720-3102, USA.

    Background: Nonsense-mediated mRNA decay (NMD) is a eukaryotic mRNA surveillance mechanism that detects and degrades mRNAs with premature termination codons (PTC+ mRNAs). In mammals, a termination codon is recognized as premature if it lies more than about 50 nucleotides upstream of the final intron position. More than a third of reliably inferred alternative splicing events in humans have been shown to result in PTC+ mRNA isoforms. As the mechanistic details of NMD have only recently been elucidated, we hypothesized that many PTC+ isoforms may have been cloned, characterized and deposited in the public databases, even though they would be targeted for degradation in vivo.

    Results: We analyzed the human alternative protein isoforms described in the SWISS-PROT database and found that 144 (5.8% of 2,483) isoform sequences amenable to analysis, from 107 (7.9% of 1,363) SWISS-PROT entries, derive from PTC+ mRNA.

    Conclusions: For several of the PTC+ isoforms we identified, existing experimental evidence can be reinterpreted and is consistent with the action of NMD to degrade the transcripts. Several genes with mRNA isoforms that we identified as PTC+--calpain-10, the CDC-like kinases (CLKs) and LARD--show how previous experimental results may be understood in light of NMD.

    Funded by: NHGRI NIH HHS: K22 HG000056, K22 HG00056, T32 HG000047, T32 HG00047

    Genome biology 2004;5;2;R8

  • Comparative distribution of tau phosphorylated at Ser262 in pre-tangles and tangles.

    Lauckner J, Frey P and Geula C

    Laboratory for Neurodegenerative and Aging Research, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.

    The Phospho-Ser(262) epitope of phosphorylated tau, which accumulates in tangles in Alzheimer's disease (AD) brains, has been shown to have a strong disruptive effect on microtubules. Using antibodies which specifically recognize the Phospho-Ser(262) of tau, we compared the presence of this epitope in normal appearing neurons (pre-tangles) and tangles, with the presence of Phospho-Ser(199/202) (AT-8) and Phospho-Ser(396/404) (PHF-1) epitopes. All antibodies visualized lightly or darkly stained pre-tangles, neurons with immunoreactive clumps, intracellular and extracellular tangles. Pre-tangles were more abundant in control cases which showed some pathology, when compared with AD brains. Immunoreactivity for Phospho-Ser(262) was preferentially present in intracellular and extracellular tangles and was found in a significantly smaller number of pre-tangles when compared with the other epitopes. These results indicate the presence of various epitopes of Phospho-Tau in a substantial number of pre-tangles which may represent an early marker of tangle formation. The differential distribution of various epitopes suggests that the presence of the Phospho-Ser(262) epitope of tau either accelerates the transition form pre-tangle to tangle, or appears later than the other epitopes in the process of tangle formation.

    Funded by: NIA NIH HHS: AG14706

    Neurobiology of aging 2003;24;6;767-76

  • Interphase and monoastral-mitotic phenotypes of overexpressed MAP4 are modulated by free tubulin concentrations.

    Holmfeldt P, Brattsand G and Gullberg M

    Department of Molecular Biology, University of Umea, S-901 87 Umea, Sweden.

    The microtubule-associated protein 4 (MAP4) has recently been shown to counteract destabilization of interphase microtubules caused by catastrophe promotion but not by tubulin sequestering. To address how MAP4 discriminates between destabilization of microtubules by these two mechanisms, we have evaluated the combined phenotypes of MAP4 coexpressed with Op18/stathmin family member derivatives with either catastrophe-promoting or sequestering activities. This approach relies on the finding that overexpression of MAP4 alone stabilizes microtubules during all phases of the cell cycle in human leukemia cells, and causes a potent mitotic block and a dramatic, previously unobserved, phenotype characterized by large monoastral spindles. Coexpression of either catastrophe-promoting or tubulin-sequestration-specific Op18 derivatives was found to modulate the activity of ectopic MAP4 during mitosis, but with differential functional outcome. Interestingly, the tubulin-sequestering derivative suppressed the monoastral mitotic phenotype of MAP4 (i.e. coexpression facilitated the formation of functional spindles). To evaluate whether this phenotypic suppression could be explained by tubulin-sequestration-dependent modulation of MAP4 activity, a plasma-membrane-targeted, tubulin-sequestering chimera was constructed to decrease the cytosolic free tubulin concentration substantially. This chimera likewise suppressed the monoastral phenotype caused by overexpression of MAP4, suggesting a direct downregulation of MAP4 activity by reduced free tubulin concentrations.

    Journal of cell science 2003;116;Pt 18;3701-11

  • Specific binding of dehydroepiandrosterone to the N terminus of the microtubule-associated protein MAP2.

    Laurine E, Lafitte D, Grégoire C, Sérée E, Loret E, Douillard S, Michel B, Briand C and Verdier JM

    Ecole Pratique des Hautes Etudes, Université Montpellier II, Place Eugène Bataillon, CC94, 34095 Montpellier cedex 05, France.

    The effect of neurosteroids is mediated through their membrane or nuclear receptors. However, no dehydroepiandrosterone (DHEA)-specific receptors have been evidenced so far in the brain. In this paper, we showed by isothermal titration calorimetry that the DHEA specifically binds to the dendritic brain microtubule-associated protein MAP2C with an association constant of 2.7 x 10(7) m-1 and at a molar ratio of 1:1. By partial tryptic digestions and mass spectrometry analysis, we found that the binding involved the N-terminal region of MAP2C. Interestingly, MAP2C displays homologies with 17 beta-hydroxysteroid dehydrogenase 1, an enzyme required for estrogen synthesis. Based on these sequence homologies and on the x-ray structure of the DHEA-binding pocket of 17 beta-hydroxysteroid dehydrogenase 1, we modeled the complex of DHEA with MAP2C. The binding of DHEA to MAP2C involved specific hydrogen bonds that orient the steroid into the pocket. This work suggests that DHEA can directly influence brain plasticity via MAP2C binding. It opens interesting ways for understanding the role of DHEA in the brain.

    The Journal of biological chemistry 2003;278;32;29979-86

  • Facilitation of dendritic mRNA transport by CPEB.

    Huang YS, Carson JH, Barbarese E and Richter JD

    Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

    In neurons, the proteins derived from mRNAs localized in dendrites have been implicated in synaptic plasticity. The cytoplasmic polyadenylation element (CPE), a cis element in the 3'-UTRs of specific dendritic mRNAs, promotes cytoplasmic polyadenylation-induced translation in response to synaptic stimulation. Here, we demonstrate that the CPE and its binding protein CPEB facilitate mRNA transport to dendrites. In rat hippocampal neurons infected with recombinant viruses, the CPE is sufficient to direct a reporter RNA into dendrites. CPEB-GFP protein forms RNA-containing particles that are transported into dendrites in a microtubule-dependent fashion at an average velocity of 4-8 microm/min. Such particles also contain maskin, a CPEB-associated factor that mediates cap-dependent translational repression of CPE-containing mRNA, and the molecular motors dynein and kinesin. Overexpression of CPEB in neurons promotes the transport of CPE-containing endogenous MAP2 mRNA to dendrites, whereas overexpression of a mutant CPEB that is defective for interaction with molecular motors inhibits this transport. In neurons derived from CPEB knockout mice, the dendritic transport of a CPE-containing reporter RNA is reduced. These results suggest a mechanism whereby CPE-containing mRNAs can be transported to dendrites in a translationally dormant form, but activated at synapses in response to NMDA receptor stimulation.

    Funded by: NIDDK NIH HHS: DK32520, P30 DK032520; NINDS NIH HHS: NS15190, NS39321, P01 NS039321, R01 NS015190, R56 NS015190

    Genes & development 2003;17;5;638-53

  • Diagnostic value of microtubule-associated protein-2 (MAP-2) for neuroendocrine neoplasms.

    Liu Y, Saad RS, Shen SS and Silverman JF

    Department of Pathalogy and Laboratory Medicine, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, USA.

    Microtubule associated proteins (MAPs) are major components of cytoskeleton proteins associated with microtubule assembly. Microtubule associated protein-2 (MAP-2), a component of the MAP family, has been shown to be specifically expressed in neuronally differentiated cells, and has been previously used as a sensitive and specific marker for neurons. Immunoreactivity of MAP-2 has been demonstrated in most neuroendocrine and neuroectodermal related neoplasms such as small cell carcinoma, large cell neuroendocrine carcinoma, carcinoid tumor of the lung, Merkel cell carcinoma of the skin, medulloblastoma, neurocytoma of the central nervous system, extrapulmonary small cell carcinoma and carcinoid tumor, and malignant melanomas. This report details the diagnostic value of MAP-2 on tumors with neuroendocrine differentiation and neoplasms derived from the neural crest.

    Advances in anatomic pathology 2003;10;2;101-6

  • In vitro assembly of Alzheimer-like filaments. How a small cluster of charged residues in Tau and MAP2 controls filament morphology.

    DeTure MA, Di Noto L and Purich DL

    Department of Biochemistry & Molecular Biology, and the McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida 32610-0245, USA.

    Although the microtubule-binding regions (MTBRs) of both Tau and MAP2 can undergo self-assembly into straight filaments (SFs) in vitro, only the Tau MTBR forms paired helical filaments (PHFs). Moreover, Tau appears to be the exclusive building block of the neuropathic filaments observed in Alzheimer's disease and certain frontotemporal dementias (FTDs). Despite significant conservation in the MTBR sequences, there are two persistently different stretches of amino acids (designated here as Module-A and Module-B) between Tau and MAP2 from a number of organisms. To evaluate the role of charged residues in these modules as potential morphology-specifying elements, we used site-directed mutagenesis to replace selected residues within the MAP2 MTBR by residues at corresponding positions in Tau. We then employed electron microscopy to determine the frequency of occurrence of SF and PHF morphology in filaments assembled from these mutant microtubule-binding regions. Our experimental results indicate that a very small number of residues are especially significant determinants of filament morphology; this inference is also supported by the observation that site-directed substitutions of individual Tau residues into MAP2 Module-B likewise result in the formation of PHF-like structures. Because the Module-B in Tau contains two naturally occurring FTD mutations, residues in this region may play a critical role in neuropathic filament assembly.

    The Journal of biological chemistry 2002;277;38;34755-9

  • MAP2 and tau bind longitudinally along the outer ridges of microtubule protofilaments.

    Al-Bassam J, Ozer RS, Safer D, Halpain S and Milligan RA

    Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037, USA.

    MAP2 and tau exhibit microtubule-stabilizing activities that are implicated in the development and maintenance of neuronal axons and dendrites. The proteins share a homologous COOH-terminal domain, composed of three or four microtubule binding repeats separated by inter-repeats (IRs). To investigate how MAP2 and tau stabilize microtubules, we calculated 3D maps of microtubules fully decorated with MAP2c or tau using cryo-EM and helical image analysis. Comparing these maps with an undecorated microtubule map revealed additional densities along protofilament ridges on the microtubule exterior, indicating that MAP2c and tau form an ordered structure when they bind microtubules. Localization of undecagold attached to the second IR of MAP2c showed that IRs also lie along the ridges, not between protofilaments. The densities attributable to the microtubule-associated proteins lie in close proximity to helices 11 and 12 and the COOH terminus of tubulin. Our data further suggest that the evolutionarily maintained differences observed in the repeat domain may be important for the specific targeting of different repeats to either alpha or beta tubulin. These results provide strong evidence suggesting that MAP2c and tau stabilize microtubules by binding along individual protofilaments, possibly by bridging the tubulin interfaces.

    Funded by: NIA NIH HHS: AG-05131, P50 AG005131; NIGMS NIH HHS: GM-52468, R01 GM052468, R37 GM052468; NIMH NIH HHS: F31 MH012504, MH-12504, MH50861, R01 MH050861, R29 MH050861

    The Journal of cell biology 2002;157;7;1187-96

  • Immunocytochemical expression of microtubule-associated protein-2 (MAP-2) in small cell lung cancer cell lines with neuronal-like processes.

    Tanaka K and Terasaki T

    Radiobiology, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045. ktanaka@ncc.go.jp

    Five of six human small cell lung cancer (SCLC) cell lines changed morphologically into cells with neuronal-like processes on the extracellular matrix of human lung adenocarcinoma cell line PC-9 cells (PC-9 / ECM substrate). The features of the neuronal-like processes of these SCLC cell lines were examined immunocytochemically using monoclonal antibodies against beta-chains of tubulin and microtubule-associated protein-2 (MAP-2), which is somatodendritic MAP of neurons. It was observed that beta-chains of tubulin and MAP-2 were expressed along the neuronal-like processes of SCLC cell lines. These findings suggest that the beta-chains of tubulin and MAP-2 are expressed functionally in SCLC cell lines in association with the development of dendrite-like processes on PC-9 / ECM substrate.

    Japanese journal of cancer research : Gann 2002;93;6;699-705

  • Microtubule-associated protein 2 (MAP-2) is expressed in low and high grade diffuse astrocytomas.

    Wharton SB, Chan KK and Whittle IR

    Department of Pathology, University of Edinburgh, Cambridge, UK.

    The expression of neuronal antigens in diffuse astrocytomas has not been thoroughly evaluated. We have investigated the expression of microtubule associated protein 2 (MAP-2), synaptophysin and non-phosphorylated epitopes of neurofilament protein (NFP) by immunohistochemistry in 15 low grade diffuse astrocytomas and 15 glioblastomas. MAP-2 was strongly expressed in 97% of cases, using an antibody to both low and high molecular weight isoforms. An antibody specific to high molecular weight isoforms of MAP-2 (hmw-MAP-2) revealed weaker, focal staining in 60% of cases with greater expression in the glioblastomas (P=0.027). NFP was expressed in 50% of cases, but was generally weak and focal. There was little evidence of synaptophysin expression. We conclude that MAP-2 expression in astrocytomas is due predominantly to low molecular weight isoforms, which may be expressed in astrocytes as well as neurons. Focal expression of hmw-MAP-2 and NFP, however, suggest that neuronal antigens may be expressed, particularly in high grade astrocytomas. Immunopositivity for these antigens should not preclude the diagnosis of diffuse astrocytoma.

    Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia 2002;9;2;165-9

  • Binding of Fyn to MAP-2c through an SH3 binding domain. Regulation of the interaction by ERK2.

    Zamora-Leon SP, Lee G, Davies P and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

    Microtubule-associated protein 2 (MAP-2) isoforms are developmentally expressed in the nervous system and contain a number of functional domains. Adjacent to the first repeat of the microtubule-binding domain is an RTPPKSP motif for binding SH3 domains. To identify SH3-containing proteins that interact with MAP-2, transfections, filter overlay assays, glutathione S-transferase (GST)-mediated binding assays, co-immunoprecipitations and enzyme-linked immunosorbent assays were performed. Transfections of MAP-2a, MAP-2b, and MAP-2c constructs into COS7 cells, followed by incubation of the cell lysates with SH3-GST fusion proteins, determined that the strongest interaction was between MAP-2c and the non-receptor tyrosine kinase Fyn; however, MAP-2b and MAP-2c also bound to Grb2. Co-immunoprecipitation of Fyn and MAP-2c from human fetal homogenates confirmed the interaction in vivo. MAP-2 synthetic peptides spanning the RTPPKSP motif bound to Fyn, and the interaction was regulated by phosphorylation. Co-transfections with MAP-2c and the extracellular signal-regulated kinase 2 (ERK2) demonstrated that MAP-2c is threonine/serine-phosphorylated on its RTPPKSP motif and that threonine phosphorylation abolished the MAP-2c/Fyn binding. Kinase assays and co-transfection of MAP-2c and Fyn confirmed that Fyn tyrosine kinase phosphorylates MAP-2c. Thus, the activation of signaling pathways may regulate cytoskeletal dynamics by altering the state of phosphorylation of MAP-2 by both ERK2 and Fyn kinase.

    Funded by: NIMH NIH HHS: MH 38623; NINDS NIH HHS: NS 32100, NS 38102

    The Journal of biological chemistry 2001;276;43;39950-8

  • Myosin VIIA is specifically associated with calmodulin and microtubule-associated protein-2B (MAP-2B).

    Todorov PT, Hardisty RE and Brown SD

    MRC Mammalian Genetics Unit and UK Mouse Genome Centre, Harwell OX11 0RD, U.K.

    Myosin VIIA is a motor molecule with a conserved head domain and tail region unique to myosin VIIA, which probably defines its unique function in vivo. In an attempt to further characterize myosin VIIA function we set out to identify molecule(s) that specifically associate with it. We demonstrate that 17 and 55 kDa proteins from mouse kidney and cochlea co-purify with myosin VIIA on affinity columns carrying immobilized anti-myosin VIIA antibody. N-terminal sequencing and immunoblotting analysis identified the 17 kDa protein as calmodulin, whereas MS and immunoblotting analysis identified the 55 kDa protein as microtubule-associated protein-2B (MAP-2B). Myosin VIIA can also be co-immunoprecipitated from kidney homogenate using anti-calmodulin or anti-MAP2 (recognizing isoforms 2A and 2B) antibodies, confirming the strong association between calmodulin and myosin VIIA and between MAP-2B and myosin VIIA. Myosin VIIA binds to calmodulin with an apparent K(d) of 10(-9) M. Scatchard analysis of the binding of myosin VIIA to MAP-2B provided evidence for two binding sites, with K(d) values of 10(-10) and 10(-9) M, which have been mapped to medial and C-terminal tail domains of myosin VIIA. The characterization of the interaction of calmodulin and MAP-2B with myosin VIIA provides new insights into the function of myosin VIIA.

    The Biochemical journal 2001;354;Pt 2;267-74

  • Phosphorylation-dependent localization of microtubule-associated protein MAP2c to the actin cytoskeleton.

    Ozer RS and Halpain S

    Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.

    Microtubule-associated protein 2 (MAP2) is a neuronal phosphoprotein that promotes net microtubule growth and actin cross-linking and bundling in vitro. Little is known about MAP2 regulation or its interaction with the cytoskeleton in vivo. Here we investigate the in vivo function of three specific sites of phosphorylation on MAP2. cAMP-dependent protein kinase activity disrupts the MAP2-microtubule interaction in living HeLa cells and promotes MAP2c localization to peripheral membrane ruffles enriched in actin. cAMP-dependent protein kinase phosphorylates serines within three KXGS motifs, one within each tubulin-binding repeat. These highly conserved motifs are also found in homologous proteins tau and MAP4. Phosphorylation at two of these sites was detected in brain tissue. Constitutive phosphorylation at these sites was mimicked by single, double, and triple mutations to glutamic acid. Biochemical and microscopy-based assays indicated that mutation of a single residue was adequate to disrupt the MAP2-microtubule interaction in HeLa cells. Double or triple point mutation promoted MAP2c localization to the actin cytoskeleton. Specific association between MAP2c and the actin cytoskeleton was demonstrated by retention of MAP2c-actin colocalization after detergent extraction. Specific phosphorylation states may enhance the interaction of MAP2 with the actin cytoskeleton, thereby providing a regulated mechanism for MAP2 function within distinct cytoskeletal domains.

    Funded by: NIMH NIH HHS: F31 MH012504, MH-12504, MH-50861, R01 MH050861, R29 MH050861

    Molecular biology of the cell 2000;11;10;3573-87

  • Regulated association of microtubule-associated protein 2 (MAP2) with Src and Grb2: evidence for MAP2 as a scaffolding protein.

    Lim RW and Halpain S

    Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.

    Microtubule-associated protein 2 (MAP2) and tau, which is involved in Alzheimer's disease, are major cytoskeletal proteins in neurons. These proteins are involved in microtubule assembly and stability. To further characterize MAP2, we took a strategy of identifying potential MAP2 binding partners. The low molecular weight MAP2c protein has 11 PXXP motifs that are conserved across species, and these PXXP motifs could be potential ligands for Src homology 3 (SH3) domains. We tested for MAP2 interaction with SH3 domain-containing proteins. All neuronal MAP2 isoforms bound specifically to the SH3 domains of c-Src and Grb2 in an in vitro glutathione S-transferase-SH3 pull-down assay. Interactions between endogenous proteins were confirmed by co-immunoprecipitation using brain lysate. All three proteins were also found co-expressed in neuronal cell bodies and dendrites. Surprisingly, the SH3 domain-binding site was mapped to the microtubule-binding domain that contains no PXXP motif. Src bound primarily the soluble, non-microtubule-associated MAP2c in vitro. This specific MAP2/SH3 domain interaction was inhibited by phosphorylation of MAP2c by the mitogen-activated protein kinase extracellular signal-regulated kinase 2 but not by protein kinase A. This phosphorylation-regulated association of MAP2 with proteins of intracellular signal transduction pathways suggests a possible link between cellular signaling and neuronal cytoskeleton, with MAP2 perhaps acting as a molecular scaffold upon which cytoskeleton-modifying proteins assemble and dissociate in response to neuronal activity.

    Funded by: NIMH NIH HHS: MH 50861, R01 MH050861

    The Journal of biological chemistry 2000;275;27;20578-87

  • Proteomic analysis of NMDA receptor-adhesion protein signaling complexes.

    Husi H, Ward MA, Choudhary JS, Blackstock WP and Grant SG

    Centre for Genome Research, Centre for Neuroscience, University of Edinburgh, West Mains Road, Edinburgh EH9 3JQ, UK.

    N-methyl-d-aspartate receptors (NMDAR) mediate long-lasting changes in synapse strength via downstream signaling pathways. We report proteomic characterization with mass spectrometry and immunoblotting of NMDAR multiprotein complexes (NRC) isolated from mouse brain. The NRC comprised 77 proteins organized into receptor, adaptor, signaling, cytoskeletal and novel proteins, of which 30 are implicated from binding studies and another 19 participate in NMDAR signaling. NMDAR and metabotropic glutamate receptor subtypes were linked to cadherins and L1 cell-adhesion molecules in complexes lacking AMPA receptors. These neurotransmitter-adhesion receptor complexes were bound to kinases, phosphatases, GTPase-activating proteins and Ras with effectors including MAPK pathway components. Several proteins were encoded by activity-dependent genes. Genetic or pharmacological interference with 15 NRC proteins impairs learning and with 22 proteins alters synaptic plasticity in rodents. Mutations in three human genes (NF1, Rsk-2, L1) are associated with learning impairments, indicating the NRC also participates in human cognition.

    Nature neuroscience 2000;3;7;661-9

  • Disulfide-cross-linked tau and MAP2 homodimers readily promote microtubule assembly.

    Di Noto L, DeTure MA and Purich DL

    Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Health Science Center, Gainesville 32610-0245, USA.

    The neuronal proteins Tau and MAP2 use homologous C-terminal MT-binding regions (MTBRs) to interact with microtubules, F-actin, and intermediate filaments. Although Tau-MTBR is the principal component of pronase-treated Alzheimer paired helical filaments, both Tau and MAP2 form filaments in vitro from disulfide-linked homodimers. That the critical thiol lies within a domain needed for MT binding raised the question: Does disulfide formation block Tau-Tau or MAP2-MAP2 dimer binding to microtubules, thereby acting to divert dimers toward filament formation? We now report that cross-linked Tau and MAP2 homodimers readily promote tubulin polymerization and that monomer and dimer affinity for MTs is surprisingly similar. Therefore, disulfide cross-bridging into homodimers is unlikely to be a drive force for filament formation in Alzheimer's disease.

    Funded by: NIGMS NIH HHS: GM-44823

    Molecular cell biology research communications : MCBRC 1999;2;1;71-6

  • Making sense of the multiple MAP-2 transcripts and their role in the neuron.

    Shafit-Zagardo B and Kalcheva N

    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

    Microtubule-associated protein-2 (MAP-2) is a family of heat-stable, phosphoproteins expressed predominantly in the cell body and dendrites of neurons. Three major MAP-2 isoforms, (MAP-2a, MAP-2b, MAP-2c) are differentially expressed during the development of the nervous system and have an important role in microtubule dynamics. Several MAP-2 cDNA clones that correspond to the major MAP-2 transcripts and additional, novel MAP-2 transcripts expressed in the CNS and PNS have been characterized. The transcripts result from the alternative splicing of a single MAP-2 gene consisting of 20 exons. Studies are now being directed toward understanding the role of the multiple MAP-2 forms that contain novel exons in the nervous system. The expression, localization, and possible functions of the newly identified spliced forms are the focus of this review.

    Molecular neurobiology 1998;16;2;149-62

  • Reduction of microtubule catastrophe events by LIS1, platelet-activating factor acetylhydrolase subunit.

    Sapir T, Elbaum M and Reiner O

    Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.

    Forming the structure of the human brain involves extensive neuronal migration, a process dependent on cytoskeletal rearrangement. Neuronal migration is believed to be disrupted in patients exhibiting the developmental brain malformation lissencephaly. Previous studies have shown that LIS1, the defective gene found in patients with lissencephaly, is a subunit of the platelet-activating factor acetylhydrolase. Our results indicated that LIS1 has an additional function. By interacting with tubulin it suppresses microtubule dynamics. We detected LIS1 interaction with microtubules by immunostaining and co-assembly. LIS1-tubulin interactions were assayed by co-immunoprecipitation and by surface plasmon resonance changes. Microtubule dynamic measurements in vitro indicated that physiological concentrations of LIS1 indeed reduced microtubule catastrophe events, thereby resulting in a net increase in the maximum length of the microtubules. Furthermore, the LIS1 protein concentration in the brain, measured by quantitative Western blots, is high and is approximately one-fifth of the concentration of brain tubulin. Our new findings show that LIS1 is a protein exhibiting several cellular interactions, and the interaction with the cytoskeleton may prove to be the mode of transducing a signal generated by platelet-activating factor. We postulate that the LIS1-cytoskeletal interaction is important for neuronal migration, a process that is defective in lissencephaly patients.

    The EMBO journal 1997;16;23;6977-84

  • Phosphorylation of microtubule-associated proteins MAP2 and MAP4 by the protein kinase p110mark. Phosphorylation sites and regulation of microtubule dynamics.

    Illenberger S, Drewes G, Trinczek B, Biernat J, Meyer HE, Olmsted JB, Mandelkow EM and Mandelkow E

    Max-Planck-Unit for Structural Molecular Biology, Hamburg, Germany.

    The phosphorylation of microtubule-associated proteins (MAPs) is thought to be a key factor in the regulation of microtubule stability. We have shown recently that a novel protein kinase, termed p110 microtubule-affinity regulating kinase ("MARK"), phosphorylates microtubule-associated protein tau at the KXGS motifs in the region of internal repeats and causes the detachment of tau from microtubules (Drewes, G., Trinczek, B., Illenberger, S., Biernat, J., Schmitt-Ulms, G., Meyer, H.E., Mandelkow, E.-M., and Mandelkow, E. (1995) J. Biol. Chem. 270, 7679-7688). Here we show that p110mark phosphorylates analogous KXGS sites in the microtubule binding domains of the neuronal MAP2 and the ubiquitous MAP4. Phosphorylation in vitro leads to the dissociation of MAP2 and MAP4 from microtubules and to a pronounced increase in dynamic instability. Thus, the phosphorylation of the repeated motifs in the microtubule binding domains of MAPs by p110mark might provide a mechanism for the regulation of microtubule dynamics in cells.

    The Journal of biological chemistry 1996;271;18;10834-43

  • Morphological, biochemical, and genetic support for an apolipoprotein E effect on microtubular metabolism.

    Roses AD, Einstein G, Gilbert J, Goedert M, Han SH, Huang D, Hulette C, Masliah E, Pericak-Vance MA, Saunders AM, Schmechel DE, Strittmatter WJ, Weisgraber KH and Xi PT

    Department of Medicine (Neurology), Duke University Medical Center, Durham, North Carolina 27710, USA.

    There are two distinct viewpoints on the association of the inheritance of apolipoprotein E (APOE) alleles and the age of onset distribution of Alzheimer's disease (AD): genetic and phenotypic expression. There have been multiple corroborations of the APOE-epsilon 4 association with Alzheimer's disease in populations around the world in clinic based studies as well as emerging epidemiological studies. The genetic data do not imply mechanism of pathogenesis. The phenotypic expression of AD has been based in theories based on amyloid plaques or neurofibrillary tangles. ApoE protein interacts with both beta-amyloid and tau in an isoform-specific manner. The interaction with tau had been thought to be an in vitro artifact, since apoE had not been previously localized to the neuronal cytoplasm. Immuno-EM studies have localized apoE in neuronal cytoplasm. ApoE3 interacts with both tau and MAP2c at the microtubule binding repeat domain under conditions in which apoE4 is less tightly bound. These data further support a hypothesis that apoE3 (and apoE2) protect the microtubule binding domain of tau from binding to itself to form paired helical filaments and neurofibrillary tangles, while protecting the site for microtubule stabilizing interactions with beta-tubulin. These data are supported by recent data from APOE knock-out mice demonstrating dendritic alterations leading to synaptic simplification similar to that observed in AD.

    Funded by: NHLBI NIH HHS: HL-41633; NIA NIH HHS: 5P50 AG-05128, 5R35 AG-07922; ...

    Annals of the New York Academy of Sciences 1996;777;146-57

  • The cleavage of host cell proteins by HIV-1 protease.

    Snásel J and Pichová I

    Department of Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.

    Folia biologica 1996;42;5;227-30

  • Genomic structure of human microtubule-associated protein 2 (MAP-2) and characterization of additional MAP-2 isoforms.

    Kalcheva N, Albala J, O'Guin K, Rubino H, Garner C and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

    We have determined that the gene for human microtubule-associated protein 2 (MAP-2) spans 19 exons, including 6 exons identified in this study, 1-4, 8, and 13; all six of these exons are transcribed. The alternative splicing of coding exons generates a greater diversity of MAP-2 transcripts and isoforms. The first three exons encode alternate 5' untranslated regions that can be spliced to additional untranslated sequences contained in exons 4 and 5. Exons 8 and 13 are transcribed in human fetal spinal cord, adult brain, MSN cells, and rat brain, and each exon maintains an open reading frame with both high and low molecular weight MAP-2 isoforms. Antibodies generated to synthetic peptides of exons 8 and 13 demonstrate that these exons are translated and MAP-2 isoforms containing these exons are generated.

    Proceedings of the National Academy of Sciences of the United States of America 1995;92;24;10894-8

  • A novel tau-tubulin kinase from bovine brain.

    Takahashi M, Tomizawa K, Sato K, Ohtake A and Omori A

    Mitsubishi Kasei Institute of Life Sciences (Project 2), Tokyo, Japan.

    During purification of tau protein kinase I and II from the bovine brain extract, a new tau protein kinase was detected and purified with phosphocellulose, gel filtration, S-Sepharose and AF-Heparin column chromatography. The molecular mass of the enzyme was determined to be 32 kDa by gel filtration and activity staining on SDS-PAGE. The enzyme is a Ser/Thr protein kinase phosphorylating tau, beta-tubulin, MAP2 and alpha-casein. Employing many synthetic peptides, the recognition site of this enzyme appears to be -SR-. The enzyme requires no second messenger and is inhibited with high concentration of heparin, but not by inhibitors of CKI. These results indicate that this enzyme, tau-tubulin kinase is novel and distinct from TPKI, II and CKI, II.

    FEBS letters 1995;372;1;59-64

  • Four repeat MAP2 isoforms in human and rat brain.

    Kindler S and Garner CC

    California Institute of Technology, Division of Biology 216-76, Pasadena 91125.

    In mammalian brain, variations in the primary structure of the characterized microtubule-associated protein 2 (MAP2) isoforms have only been observed in their projection domains whose length determines the spacing between neighboring microtubules. We now report that, as with MAP4 and tau, MAP2 isoforms containing four (4R) instead of three (3R) tandem repeats in their microtubule binding domains do exist in human and rat brain. The additional sequence, inserted between the first and second repeat of the 3R-MAP2 messages, appears on mRNAs encoding both high and low molecular weight (Hwt and Lwt) rat MAP2 variants. In contrast to the corresponding 3R-messages, 4R-Hwt MAP2 concentrations decrease during early postnatal rat brain development, while the amount of 4R-Lwt MAP2 messages remains constant. In general, 4R-/3R-MAP2 mRNA ratios appear to be low with the highest levels of 4R-messages found in the cerebellum.

    Brain research. Molecular brain research 1994;26;1-2;218-24

  • Characterization of the transcripts encoding two isoforms of human microtubule-associated protein-2 (MAP-2).

    Albala JS, Kalcheva N and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461.

    Through the isolation of a series of overlapping clones from human fetal and adult cDNA libraries, we have generated the complete cDNA sequences encoding human high- and low-molecular-weight microtubule-associated protein-2 (MAP-2) which have strong sequence homology with rodent MAP-2.

    Funded by: NIA NIH HHS: AG00194, AG06803

    Gene 1993;136;1-2;377-8

  • Cleavage of bovine brain microtubule-associated protein-2 by human immunodeficiency virus proteinase.

    Ainsztein AM and Purich DL

    Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville 32610-0245.

    The high-molecular-weight dendritic cytoskeletal protein known as microtubule-associated protein (MAP)-2 displays the capacity to stimulate tubulin polymerization and to associate with microtubules. Serine proteases cleave MAP-2 into a C-terminal M(r) 28,000-35,000 microtubule-binding fragment and a larger N-terminal M(r) 240,000 projection-arm region. We now show that human immunodeficiency virus (HIV) proteinase also progressively degrades purified MAP-2 in vitro. This proteolysis reaction is characterized by transient accumulation of at least six intermediates, and most abundant of these is an M(r) 72,000 species that retains the ability to associate with taxol-stabilized microtubules. Treatment of this M(r) 72,000 species with thrombin releases the same M(r) 28,000 component as that derived from thrombin action on intact high-molecular-weight MAP-2, indicating that the viral aspartoproteinase action preferentially occurs further toward the N-terminus. The association of the M(r) 72,000 component with microtubules can be disrupted by the presence of a 21-amino acid peptide analogue of the second repeated sequence in the MAP-2 microtubule-binding region. We also studied HIV proteinase action on MAP-2 in the presence of tubulin and other MAPs that recycle with tubulin, and contrary to other published studies we found no effect of such treatment on microtubule self-assembly behavior. Cleavage of isolated MAP-2 by the HIV enzyme at high salt concentrations, followed by desalting and addition of tubulin, also resulted in microtubule assembly, albeit with slightly reduced efficiency.

    Journal of neurochemistry 1992;59;3;874-80

  • Interaction domains of neurofilament light chain and brain spectrin.

    Frappier T, Stetzkowski-Marden F and Pradel LA

    C.N.R.S. U.A. 1089, Laboratoire de Biophysique, Institut de Biologie Physico-Chimique, Paris, France.

    We have previously demonstrated that brain spectrin binds to the low-molecular-mass subunit of neurofilaments (NF-L) [Frappier, Regnouf & Pradel (1987) Eur. J. Biochem. 169, 651-657]. In the present study, we seek to locate their respective binding domains. In the first part we demonstrate that brain spectrin binds to a 20 kDa domain of NF-L. This domain is part of the rod domain of neurofilaments and plays a role in the polymerization process. However, the polymerization state does not seem to have any influence on the interaction. In the second part, we provide evidence that NF-L binds to the beta-subunit of not only brain spectrin but also human and avian erythrocyte spectrins. The microtubule-associated protein, MAP2, which has also been shown to bind to microfilaments and neurofilaments, binds to the same domain of NF-L as spectrin does. Finally, among the tryptic peptides of brain spectrin, we show that some peptides of low molecular mass (35, 25, 20 and 18 kDa) co-sediment with either NF-L or F-actin.

    The Biochemical journal 1991;275 ( Pt 2);521-7

  • MspI RFLP for microtubule associated protein-2 (MAP2).

    Alberts MJ, Kandt RS, Pericak-Vance MA, Bebout J, Speer MC, Siddique TS, Yamaoka L, Hung WY, Gaskell PC and Roses AD

    Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Medicine, Duke University Medical Center, Durham 27710.

    Funded by: NIA NIH HHS: AG05128, AG07922; NINDS NIH HHS: NS01241

    Nucleic acids research 1991;19;4;960

  • Proteolytic cleavage of microtubule-associated proteins by retroviral proteinases.

    Wallin M, Deinum J, Goobar L and Danielson UH

    Department of Zoophysiology, University of Göteborg, Sweden.

    Aspartic proteinases from human immunodeficiency virus type 1 (HIV-1) and avian myeloblastosis virus (AMV) were found to interfere with microtubule assembly. Preincubation of the proteinases with purified brain microtubule proteins (tubulin and microtubule-associated proteins) at low ionic strength (pH 6.8), completely inhibited microtubule assembly. Analysis of microtubule proteins after incubation with proteinase showed no effect on tubulin but extensive cleavage of the microtubule-associated proteins 1 and 2 was observed. The digestion by the two proteinases differed. In the presence of HIV-1 proteinase, a fragment with an Mr of approximately 300, appeared, as well as at least three other new fragments, with Mr values of 188,000, 124,000 and 73,000. In the presence of AMV proteinase, the microtubule-associated proteins were extensively digested to many small fragments. The extending microtubule-associated proteins normally seen by electron microscopy on the microtubule surface disappeared after treatment with AMV proteinase. Our results show that retroviral proteinases are not restricted to cleavage of viral polyproteins in vitro. It is suggested that proteolysis of microtubular proteins by viral proteinases is an important step in viral pathogenicity and that it may be part of a mechanism causing degenerative effects in infected cells.

    The Journal of general virology 1990;71 ( Pt 9);1985-91

  • Sequence of a human MAP-2 region sharing epitopes with Alzheimer neurofibrillary tangles.

    Dammerman M, Yen SH and Shafit-Zagardo B

    Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461.

    Microtubule-associated protein 2 (MAP-2), an abundant neuronal protein, consists of a short microtubule-binding domain and a long projection arm. MAP-2 shares epitopes with Alzheimer neurofibrillary tangles (NFT). However, most anti-MAP-2 antibodies do not stain detergent-extracted NFT, and the role of MAP-2 in NFT formation has therefore been unclear. We have determined the sequence of a 1.7 kb partial MAP-2 cDNA encoding at least three NFT epitopes. The epitopes are not removed by detergent extraction of tangle preparations, suggesting that they are integral components of NFT. Expression vectors containing restriction fragments of the cDNA were used to assign the epitopes to a 51-amino-acid region near the end of the MAP-2 projection arm, distal to the microtubule.

    Funded by: NIA NIH HHS: AG06803, AG1136, AG4145

    Journal of neuroscience research 1989;24;4;487-95

  • The RII subunit of cAMP-dependent protein kinase binds to a common amino-terminal domain in microtubule-associated proteins 2A, 2B, and 2C.

    Obar RA, Dingus J, Bayley H and Vallee RB

    Cell Biology and Neurobiology Groups, Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.

    Three products of the MAP2 gene are known: MAP2A and MAP2B (Mr approximately 200,000) and MAP2C (Mr 70,000). The structural relationship between these MAPs and the basis for their diversity in size are unknown. Previously, we found that a significant fraction of type II cAMP-dependent protein kinase was associated via its regulatory subunits with MAP2A and MAP2B. We now use an antibody prepared against the microtubule binding domain of MAP2A and MAP2B to identify MAP2C. All three forms of MAP2 bound to cAMP affinity columns and reacted with 32P-labeled RII in a blot overlay assay. By assaying proteolytic fragments of MAP2A and MAP2B as well as segments of MAP2 expressed in E. coli, the binding site for RII was localized to an 83 amino acid stretch at the distal (amino-terminal) end of the MAP2 arm domain. Therefore, the microtubule binding and RII binding domains are located at extreme opposite ends of MAP2A and MAP2B, and both are conserved in the much shorter MAP2C.

    Funded by: NICHD NIH HHS: HD07312; NIGMS NIH HHS: GM26701

    Neuron 1989;3;5;639-45

  • Localization and characterization of the binding site for the regulatory subunit of type II cAMP-dependent protein kinase on MAP2.

    Rubino HM, Dammerman M, Shafit-Zagardo B and Erlichman J

    Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461.

    Microtubule-associated protein 2 (MAP2) binds, and is a substrate for, type II cAMP-dependent protein kinase. The structural domain in MAP2 that binds the regulatory subunit (RII) of protein kinase II was identified by expressing fragments of a human MAP2 cDNA in E. coli using the pATH11 vector. Fusion proteins were resolved by SDS-PAGE and transferred to nitrocellulose. The filters were probed with purified bovine heart or brain RII, anti-RII monoclonal antibodies, and 125I-labeled protein A. Binding of RII was localized to a 31 amino acid sequence near the N-terminus of the MAP2 molecule. Fusion proteins containing this fragment bound both heart and brain RIIs in a concentration-dependent manner, but bound heart RII with a higher apparent affinity than brain RII. The amino acid sequence of this fragment (DRETAEEVSARIVQVVTAEAVAVLKGEQEKE) is totally conserved between human and mouse MAP2, suggesting an important role for the RII binding site of MAP2 in neuronal function.

    Funded by: NIA NIH HHS: AG-06803; NIDDK NIH HHS: DK-27736

    Neuron 1989;3;5;631-8

  • Selective localization of messenger RNA for cytoskeletal protein MAP2 in dendrites.

    Garner CC, Tucker RP and Matus A

    Friedrich Miescher-Institut, Basel, Switzerland.

    For nerve cells to develop their highly polarized form, appropriate structural molecules must be targeted to either axons or dendrites. This could be achieved by the synthesis of structural proteins in the cell body and their sorting to either axons or dendrites by specific transport mechanisms. For dendrites, an alternative possibility is that proteins could be synthesized locally in the dendritic cytoplasm. This is an attractive idea because it would allow regulation of the production of structural molecules in response to local demand during dendritic development. The feasibility of dendritic protein synthesis is suggested both by the existence of dendritic polyribosomes and by the recent demonstration that newly synthesized RNA is transported into the dendrites of neurons differentiating in culture. However, to date there has been no demonstration of the selective synthesis of an identified dendrite-specific protein in the dendritic cytoplasm. Here, we use in situ hybridization with specific complementary DNA probes to show that messenger RNA for the dendrite-specific microtubule-associated protein MAP2 (refs 3-5) is present in dendrites in the developing brain. By contrast the mRNA for tubulin, a protein present in both axons and dendrites is located exclusively in neuronal cell bodies.

    Nature 1988;336;6200;674-7

  • Partial sequence of MAP2 in the region of a shared epitope with Alzheimer neurofibrillary tangles.

    Kosik KS, Orecchio LD, Bakalis S, Duffy L and Neve RL

    Department of Neurology (Neuroscience), Harvard Medical School, Boston, Massachusetts.

    A 3.3-kilobase DNA complementary to human microtubule-associated protein 2 (MAP2) was sequenced by the dideoxy method. The 3' end terminates at an internal EcoRI site before the polyA tail. Due to the arrangement of the cDNA insert in the lambda gt11 vector, the MAP2 fragment is not fused to beta-galactosidase when expressed. The Chou Fasman algorithm for the initial 58 amino acids from the first in-frame methionine predicts an alpha helix. Beyond this point, a series of turns is predicted until amino acid 160. The frequent presence of basic residues in proximity to serines or threonines is consistent with multiple phosphorylation sites. The minimum specificity determinant for Ca2+/calmodulin-dependent kinase is repeated 13 times. The sequence of a region containing a MAP2 epitope that is shared with the Alzheimer neurofibrillary tangle was determined by DNase treatment of the cDNA and antibody selecting the small resultant clones in a lambda gt11 sublibrary. Likewise, a MAP2 epitope that is not shared with the neurofibrillary tangle also has been located. Both epitopes are in the projection portion of the molecule. A bovine MAP2 cyanogen bromide fragment, which contains the epitope shared with the neurofibrillary tangle, is partially insoluble under aqueous conditions, probably due to the aggregation of oppositely charged residues. Thus, rapid cleavage of MAP2 to small peptides is probably necessary in vivo to prevent the aggregation of larger cleavage fragments.

    Funded by: NIA NIH HHS: R01 AG06172; NICHD NIH HHS: HD18658; NINDS NIH HHS: K07 NS00835; ...

    Journal of neurochemistry 1988;51;2;587-98

  • Plectin and IFAP-300K are homologous proteins binding to microtubule-associated proteins 1 and 2 and to the 240-kilodalton subunit of spectrin.

    Herrmann H and Wiche G

    Structural and functional characteristics of plectin from intermediate filament preparations of rat glioma C6 cells were compared to those of the intermediate filament-associated protein of Mr = 300,000 (IFAP-300K) of baby hamster kidney cells (Yang, H.-S., Lieska, N., Goldman, A.E., and Goldman, R.D. (1985) J. Cell Biol. 100, 620-631). After radiolabeling and proteolytic digestion under varied conditions, both proteins yielded nearly identical peptide maps. Immunological cross-reactivity, co-migration on one- and two-dimensional high-resolution gels, chromatofocusing, and amino acid analysis demonstrated structural homology as well. In vivo labeling with 32Pi showed that plectin was the target for cAMP-independent protein kinases which phosphorylated 18-kDa domains at the end(s) of the molecule. Previously reported phosphorylation sites for cAMP-dependent and a newly identified site for Ca2+/calmodulin-dependent protein kinases were located on different domains. In solid-phase binding assays, plectin bound to vimentin, microtubule-associated proteins 1 and 2, the 240-kDa chain of brain fodrin, and alpha-spectrin from human erythrocytes. Similar characteristics were revealed for corresponding 300-kDa components of various other cell lines, supporting the concept that plectin is a general cytoskeletal cross-linking element, probably of multiple function.

    The Journal of biological chemistry 1987;262;3;1320-5

  • Identification of cDNA clones for the human microtubule-associated protein tau and chromosomal localization of the genes for tau and microtubule-associated protein 2.

    Neve RL, Harris P, Kosik KS, Kurnit DM and Donlon TA

    We have previously identified a partial human cDNA for MAP2, and we now report the isolation of human cDNA clones for tau. The RNA species recognized by the tau clones is a 6 kilobase (kb) message that is expressed in the human brain but not in other human tissues, and exhibits a developmental shift in size. We also report the human chromosomal localization of the MAP2 and tau genes. The MAP2 cDNA pKN7 was used to localize the MAP2 gene to chromosome 2q34-35. The tau cDNAs were used to confirm the presence of a tau gene on chromosome 17q21 and an additional region of homology on chromosome 6p21.

    Funded by: NICHD NIH HHS: HD18658, HD20118, P30 HD18655; ...

    Brain research 1986;387;3;271-80

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
L00000013 G2C Homo sapiens Human mGluR5 Human orthologues of mouse mGluR5 complex adapted from Collins et al (2006) 52
L00000015 G2C Homo sapiens Human NRC Human orthologues of mouse NRC adapted from Collins et al (2006) 186
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000034 G2C Homo sapiens Pocklington H3 Human orthologues of cluster 3 (mouse) from Pocklington et al (2006) 30
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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