G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
phosphatidylinositol-4-phosphate 5-kinase, type I, gamma
G00000425 (Mus musculus)

Databases (7)

ENSG00000186111 (Ensembl human gene)
23396 (Entrez Gene)
782 (G2Cdb plasticity & disease)
PIP5K1C (GeneCards)
606102 (OMIM)
Marker Symbol
HGNC:8996 (HGNC)
Protein Sequence
O60331 (UniProt)

Synonyms (3)

  • KIAA0589
  • LCCS3
  • PIP5Kgamma

Literature (26)

Pubmed - other

  • Molecular basis for association of PIPKI gamma-p90 with clathrin adaptor AP-2.

    Kahlfeldt N, Vahedi-Faridi A, Koo SJ, Schäfer JG, Krainer G, Keller S, Saenger W, Krauss M and Haucke V

    Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany.

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) is an essential determinant in clathrin-mediated endocytosis (CME). In mammals three type I phosphatidylinositol-4-phosphate 5-kinase (PIPK) enzymes are expressed, with the I gamma-p90 isoform being highly expressed in the brain where it regulates synaptic vesicle (SV) exo-/endocytosis at nerve terminals. How precisely PI(4,5)P(2) metabolism is controlled spatially and temporally is still uncertain, but recent data indicate that direct interactions between type I PIPK and components of the endocytic machinery, in particular the AP-2 adaptor complex, are involved. Here we demonstrated that PIPKI gamma-p90 associates with both the mu and beta2 subunits of AP-2 via multiple sites. Crystallographic data show that a peptide derived from the splice insert of the human PIPKI gamma-p90 tail binds to a cognate recognition site on the sandwich subdomain of the beta2 appendage. Partly overlapping aromatic and hydrophobic residues within the same peptide also can engage the C-terminal sorting signal binding domain of AP-2mu, thereby potentially competing with the sorting of conventional YXXØ motif-containing cargo. Biochemical and structure-based mutagenesis analysis revealed that association of the tail domain of PIPKI gamma-p90 with AP-2 involves both of these sites. Accordingly the ability of overexpressed PIPKI gamma tail to impair endocytosis of SVs in primary neurons largely depends on its association with AP-2 beta and AP-2mu. Our data also suggest that interactions between AP-2 and the tail domain of PIPKI gamma-p90 may serve to regulate complex formation and enzymatic activity. We postulate a model according to which multiple interactions between PIPKI gamma-p90 and AP-2 lead to spatiotemporally controlled PI(4,5)P(2) synthesis during clathrin-mediated SV endocytosis.

    The Journal of biological chemistry 2010;285;4;2734-49

  • Two novel phosphatidylinositol-4-phosphate 5-kinase type Igamma splice variants expressed in human cells display distinctive cellular targeting.

    Schill NJ and Anderson RA

    Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, U.S.A.

    The generation of various phosphoinositide messenger molecules at distinct locations within the cell is mediated via the specific targeting of different isoforms and splice variants of phosphoinositide kinases. The lipid messenger PtdIns(4,5)P(2) is generated by several of these enzymes when targeted to distinct cellular compartments. Several splice variants of the type Igamma isoform of PIPK (PtdIns4P 5-kinase), which generate PtdIns(4,5)P(2), have been identified, and each splice variant is thought to serve a unique functional role within cells. Here, we have identified two novel C-terminal splice variants of PIPKIgamma in human cells consisting of 700 and 707 amino acids. These two splice variants are expressed in multiple tissue types and display PIPK activity in vitro. Interestingly, both of these novel splice variants display distinct subcellular targeting. With the addition of these two new splice isoforms, there are minimally five PIPKIgamma splice variants that have been identified in mammals. Therefore, we propose the use of the HUGO (Human Genome Organization) nomenclature in the naming of the splice isoforms. PIPKIgamma_i4 (700 amino acids) is present in the nucleus, a targeting pattern that has not been previously observed in any PIPKIgamma splice variant. PIPKIgamma_i5 (707 amino acids) is targeted to intracellular vesicle-like structures, where it co-localizes with markers of several types of endosomal compartments. As occurs with other PIPKIgamma splice variants, the distinctive C-terminal sequences of PIPKIgamma_i4 and PIPKIgamma_i5 may facilitate association with unique protein targeting factors, thereby localizing the kinases to their appropriate cellular subdomains for the site-specific generation of PtdIns(4,5)P(2).

    Funded by: NCI NIH HHS: CA104708-05; NHLBI NIH HHS: T32 HL007899-07; NIGMS NIH HHS: R01 GM057549-14

    The Biochemical journal 2009;422;3;473-82

  • PI5KI-dependent signals are critical regulators of the cytolytic secretory pathway.

    Micucci F, Capuano C, Marchetti E, Piccoli M, Frati L, Santoni A and Galandrini R

    Department of Experimental Medicine, Istituto Pasteur-Fondazione Cenci-Bolognetti, Rome, Italy.

    Although membrane phospholipid phosphatidylinositol-4,5bisphosphate (PIP2) plays a key role as signaling intermediate and coordinator of actin dynamics and vesicle trafficking, it remains completely unknown its involvement in the activation of cytolytic machinery. By live confocal imaging of primary human natural killer (NK) cells expressing the chimeric protein GFP-PH, we observed, during effector-target cell interaction, the consumption of a preexisting PIP2 pool, which is critically required for the activation of cytolytic machinery. We identified type I phosphatidylinositol-4-phosphate-5-kinase (PI5KI) alpha and gamma isoforms as the enzymes responsible for PIP2 synthesis in NK cells. By hRNA-driven gene silencing, we observed that both enzymes are required for the proper activation of NK cytotoxicity and for inositol-1,4,5-trisphosphate (IP3) generation on receptor stimulation. In an attempt to elucidate the specific step controlled by PI5KIs, we found that lytic granule secretion but not polarization resulted in impaired PI5KIalpha- and PI5KIgamma-silenced cells. Our findings delineate a novel mechanism implicating PI5KIalpha and PI5KIgamma isoforms in the synthesis of PIP2 pools critically required for IP3-dependent Ca(2+) response and lytic granule release.

    Blood 2008;111;8;4165-72

  • Type Igamma PIP kinase is a novel uropod component that regulates rear retraction during neutrophil chemotaxis.

    Lokuta MA, Senetar MA, Bennin DA, Nuzzi PA, Chan KT, Ott VL and Huttenlocher A

    Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA.

    Cell polarization is necessary for directed migration and leukocyte recruitment to inflamed tissues. Recent progress has been made in defining the molecular mechanisms that regulate chemoattractant-induced cell polarity during chemotaxis, including the contribution of phosphoinositide 3-kinase (PI3K)-dependent phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P(3)] synthesis at the leading edge. However, less is known about the molecular composition of the cell rear and how the uropod functions during cell motility. Here, we demonstrate that phosphatidylinositol phosphate kinase type Igamma (PIPKIgamma661), which generates PtdIns(4,5)P(2), is enriched in the uropod during chemotaxis of primary neutrophils and differentiated HL-60 cells (dHL-60). Using time-lapse microscopy, we show that enrichment of PIPKIgamma661 at the cell rear occurs early upon chemoattractant stimulation and is persistent during chemotaxis. Accordingly, we were able to detect enrichment of PtdIns(4,5)P(2) at the uropod during chemotaxis. Overexpression of kinase-dead PIPKIgamma661 compromised uropod formation and rear retraction similar to inhibition of ROCK signaling, suggesting that PtdIns(4,5)P(2) synthesis is important to elicit the backness response during chemotaxis. Together, our findings identify a previously unknown function for PIPKIgamma661 as a novel component of the backness signal that regulates rear retraction during chemotaxis.

    Funded by: NIAID NIH HHS: R01 AI068062, R01 AI68062; NIGMS NIH HHS: R01 GM074827

    Molecular biology of the cell 2007;18;12;5069-80

  • Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway.

    Narkis G, Ofir R, Landau D, Manor E, Volokita M, Hershkowitz R, Elbedour K and Birk OS

    Morris Kahn Laboratory of Human Genetics, National Institute of Biotechnology in Negev, Beer-Sheva, Israel.

    Lethal congenital contractural syndrome (LCCS) is a severe form of arthrogryposis. To date, two autosomal recessive forms of the disease (LCCS and LCCS2) have been described and mapped to chromosomes 9q34 and 12q13, respectively. We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder. Using 10K single-nucleotide-polymorphism arrays, we mapped the disease-associated gene to 8.8 Mb on chromosome 19p13. Further analysis using microsatallite markers narrowed the locus to a 3.4-Mb region harboring 120 genes. Of these genes, 30 candidates were sequenced, which identified a single homozygous mutation in PIP5K1C. PIP5K1C encodes phosphatidylinositol-4-phosphate 5-kinase, type I, gamma (PIPKI gamma ), an enzyme that phophorylates phosphatidylinositol 4-phosphate to generate phosphatidylinositol-4,5-bisphosphate (PIP(2)). We demonstrate that the mutation causes substitution of aspartic acid with asparagine at amino acid 253 (D253N), abrogating the kinase activity of PIPKI gamma . Thus, a defect in the phosphatidylinositol pathway leading to a decrease in synthesis of PIP(2), a molecule active in endocytosis of synaptic vesicle proteins, culminates in lethal congenital arthrogryposis.

    American journal of human genetics 2007;81;3;530-9

  • Type I gamma phosphatidylinositol phosphate kinase is required for EGF-stimulated directional cell migration.

    Sun Y, Ling K, Wagoner MP and Anderson RA

    Department of Pharmacology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706, USA.

    Phosphatidylinositol 4,5-bisphosphate (PI4,5P(2)) modulates a plethora of cytoskeletal interactions that control the dynamics of actin assembly and, ultimately, cell migration. We show that the type Igamma phosphatidylinositol phosphate kinase 661 (PIPKIgamma661), an enzyme that generates PI4,5P(2), is required for growth factor but not G protein-coupled receptor-stimulated directional migration. By generating PI4,5P(2) and regulating talin assembly, PIPKIgamma661 modulates nascent adhesion formation at the leading edge to facilitate cell migration. The epidermal growth factor (EGF) receptor directly phosphorylates PIPKIgamma661 at tyrosine 634, and this event is required for EGF-induced migration. This phosphorylation regulates the interaction between PIPKIgamma661 and phospholipase Cgamma1 (PLCgamma1, an enzyme previously shown to be involved in the regulation of EGF-stimulated migration). Our results suggest that phosphorylation events regulating specific PIPKIgamma661 interactions are required for growth factor-induced migration. These interactions in turn define the spatial and temporal generation of PI4,5P(2) and derived messengers required for directional migration.

    Funded by: NCI NIH HHS: CA104708, P30 CA014520, R01 CA104708; NIGMS NIH HHS: GM057549, R01 GM057549

    The Journal of cell biology 2007;178;2;297-308

  • Role of activation of PIP5Kgamma661 by AP-2 complex in synaptic vesicle endocytosis.

    Nakano-Kobayashi A, Yamazaki M, Unoki T, Hongu T, Murata C, Taguchi R, Katada T, Frohman MA, Yokozeki T and Kanaho Y

    Department of Physiological Chemistry, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Japan.

    Synaptic vesicles (SVs) are retrieved by clathrin-mediated endocytosis at the nerve terminals. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] drives this event by recruiting the components of the endocytic machinery. However, the molecular mechanisms that result in local generation of PI(4,5)P2 remain unclear. We demonstrate here that AP-2 complex directly interacts with phosphatidylinositol 4-phosphate 5-kinase gamma661 (PIP5Kgamma661), the major PI(4,5)P2-producing enzyme in the brain. The beta2 subunit of AP-2 was found to bind to the C-terminal tail of PIP5Kgamma661 and cause PIP5Kgamma661 activation. The interaction is regulated by PIP5Kgamma661 dephosphorylation, which is triggered by depolarization in mouse hippocampal neurons. Finally, overexpression of the PIP5Kgamma661 C-terminal region in hippocampal neurons suppresses depolarization-dependent SV endocytosis. These findings provide evidence for the molecular mechanism through which PIP5Kgamma661 locally generates PI(4,5)P2 in hippocampal neurons and suggest a model in which the interaction trigger SV endocytosis.

    Funded by: NIGMS NIH HHS: R01 GM071520, R01 GM71520

    The EMBO journal 2007;26;4;1105-16

  • Regulation of ezrin localization by Rac1 and PIPK in human epithelial cells.

    Auvinen E, Kivi N and Vaheri A

    Department of Virology, Haartman Institute, University of Helsinki, and HUSLAB Clinical Microbiology, Helsinki University Central Hospital, Helsinki, Finland. eeva.auvinen@helsinki.fi <eeva.auvinen@helsinki.fi&gt;

    Regulation of ezrin and other ERM proteins is not completely understood, but the involvement of Rho GTPases seems crucial. In this work, expression plasmids encoding full-length, deleted or truncated ezrin were constructed and coexpressed with Rac1 GTPase in HeLa human epithelial cells in order to elucidate the mechanisms of ezrin activation and function. We observed induction of actin stress fiber formation by ezrin constructs harboring the F-actin binding site but devoid of sequences required for intra- or intermolecular binding. Stress fiber-inducing ezrin mutants were localized in adherens junctions containing N-cadherin but no E-cadherin, and also colocalized with F-actin in stress fibers. This localization required the activity of Rac1 and phosphatidylinositol-4-phosphate 5-kinase and involved RhoA. We suggest that localization of ezrin in adherens junctions is regulated by Rac in a manner involving PIPK.

    Experimental cell research 2007;313;4;824-33

  • Type I gamma phosphatidylinositol phosphate kinase modulates adherens junction and E-cadherin trafficking via a direct interaction with mu 1B adaptin.

    Ling K, Bairstow SF, Carbonara C, Turbin DA, Huntsman DG and Anderson RA

    Program in Molecular and Cellular Pharmacology, Department of Pharmacology, University of Wisconsin Medical School, Madison, WI 53706, USA.

    Assembly of E-cadherin-based adherens junctions (AJ) is obligatory for establishment of polarized epithelia and plays a key role in repressing the invasiveness of many carcinomas. Here we show that type Igamma phosphatidylinositol phosphate kinase (PIPKIgamma) directly binds to E-cadherin and modulates E-cadherin trafficking. PIPKIgamma also interacts with the mu subunits of clathrin adaptor protein (AP) complexes and acts as a signalling scaffold that links AP complexes to E-cadherin. Depletion of PIPKIgamma or disruption of PIPKIgamma binding to either E-cadherin or AP complexes results in defects in E-cadherin transport and blocks AJ assembly. An E-cadherin germline mutation that loses PIPKIgamma binding and shows disrupted basolateral membrane targeting no longer forms AJs and leads to hereditary gastric cancers. These combined results reveal a novel mechanism where PIPKIgamma serves as both a scaffold, which links E-cadherin to AP complexes and the trafficking machinery, and a regulator of trafficking events via the spatial generation of phosphatidylinositol-4,5-bisphosphate.

    Funded by: NCI NIH HHS: CA104708, R01 CA104708; NIGMS NIH HHS: GM057549, R01 GM057549

    The Journal of cell biology 2007;176;3;343-53

  • Stimulation of phosphatidylinositol kinase type I-mediated phosphatidylinositol (4,5)-bisphosphate synthesis by AP-2mu-cargo complexes.

    Krauss M, Kukhtina V, Pechstein A and Haucke V

    Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany.

    Phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P(2)] is an important factor for a variety of cellular functions ranging from cell signaling to actin cytoskeletal dynamics and endocytic membrane traffic. Here, we have identified the clathrin adaptor complex AP-2 as a regulator of phosphatidylinositol 4-phosphate 5-kinase (PIPK)-mediated PI(4,5)P(2) synthesis. AP-2 directly interacts with the kinase core domain of type I PIPK isozymes via its mu2-subunit in vitro and in native protein extracts. Endocytic cargo protein binding to mu2 leads to a potent stimulation of PIPK activity. These data thus identify a positive feedback loop consisting of endocytic cargo proteins, AP-2mu, and PIPK type I which may provide a specific pool of PI(4,5)P(2) dedicated to clathrin/AP-2-dependent receptor internalization.

    Proceedings of the National Academy of Sciences of the United States of America 2006;103;32;11934-9

  • Type Igamma661 phosphatidylinositol phosphate kinase directly interacts with AP2 and regulates endocytosis.

    Bairstow SF, Ling K, Su X, Firestone AJ, Carbonara C and Anderson RA

    Department of Pharmacology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.

    Clathrin-coated vesicles mediate sorting and intracellular transport of membrane-bound proteins. The formation of these coats is initiated by the assembly of adaptor proteins (AP), which specifically bind to membrane cargo proteins via recognition of endocytic sorting motifs. The lipid signaling molecule phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) is critical for this process, as it serves as both a targeting and regulatory factor. PI(4,5)P(2) is synthesized by type I phosphatidylinositol phosphate kinases (PIPKI). We have discovered a direct interaction between the mu2-subunit of the AP2 complex and PIPKIgamma661 via a yeast two-hybrid screen. This interaction was confirmed using both the mu2-subunit in glutathione S-transferase pulldowns and via coimmunoprecipitation of endogenous PIPKIgamma661 with the AP2 complex from HEK293 cells. The interaction is mediated, in vivo, by a tyrosine-based motif in the 26-amino acid tail of PIPKIgamma661. Because AP2 regulates endocytosis of transferrin receptor from the plasma membrane, we also examined a role for PIPKIgamma661 using a flow cytometry endocytosis assay. We observed that stable expression of wild type PIPKIgamma661 in Madin-Darby canine kidney cells enhanced transferrin uptake, whereas stable expression of kinase-dead PIPKIgamma661 had an inhibitory effect. Neither condition affected the overall cellular level of PI(4,5)P(2). RNA interference-based knockdown of PIPKIgamma661 in HeLa cells also had an inhibitory effect on transferrin endocytosis using the same assay system. Collectively, this evidence implies an important role for PIPKIgamma661 in the AP2-mediated endocytosis of transferrin.

    Funded by: NCI NIH HHS: CA104708; NIGMS NIH HHS: GM08349, GM57549

    The Journal of biological chemistry 2006;281;29;20632-42

  • A human protein-protein interaction network: a resource for annotating the proteome.

    Stelzl U, Worm U, Lalowski M, Haenig C, Brembeck FH, Goehler H, Stroedicke M, Zenkner M, Schoenherr A, Koeppen S, Timm J, Mintzlaff S, Abraham C, Bock N, Kietzmann S, Goedde A, Toksöz E, Droege A, Krobitsch S, Korn B, Birchmeier W, Lehrach H and Wanker EE

    Max Delbrueck Center for Molecular Medicine, 13092 Berlin-Buch, Germany.

    Protein-protein interaction maps provide a valuable framework for a better understanding of the functional organization of the proteome. To detect interacting pairs of human proteins systematically, a protein matrix of 4456 baits and 5632 preys was screened by automated yeast two-hybrid (Y2H) interaction mating. We identified 3186 mostly novel interactions among 1705 proteins, resulting in a large, highly connected network. Independent pull-down and co-immunoprecipitation assays validated the overall quality of the Y2H interactions. Using topological and GO criteria, a scoring system was developed to define 911 high-confidence interactions among 401 proteins. Furthermore, the network was searched for interactions linking uncharacterized gene products and human disease proteins to regulatory cellular pathways. Two novel Axin-1 interactions were validated experimentally, characterizing ANP32A and CRMP1 as modulators of Wnt signaling. Systematic human protein interaction screens can lead to a more comprehensive understanding of protein function and cellular processes.

    Cell 2005;122;6;957-68

  • Critical role of PIP5KI{gamma}87 in InsP3-mediated Ca(2+) signaling.

    Wang YJ, Li WH, Wang J, Xu K, Dong P, Luo X and Yin HL

    Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.

    Phosphatidylinositol 4,5-bisphosphate (PIP(2)) is the obligatory precursor of inositol 1,4,5-trisphosphate (InsP(3) or IP(3)) and is therefore critical to intracellular Ca(2+) signaling. Using RNA interference (RNAi), we identified the short splice variant of type I phosphatidylinositol 4-phosphate 5-kinase gamma (PIP5KIgamma87) as the major contributor of the PIP(2) pool that supports G protein-coupled receptor (GPCR)-mediated IP(3) generation. PIP5KIgamma87 RNAi decreases the histamine-induced IP(3) response and Ca(2+) flux by 70%. Strikingly, RNAi of other PIP5KI isoforms has minimal effect, even though some of these isoforms account for a larger percent of total PIP(2) mass and have previously been implicated in receptor mediated endocytosis or focal adhesion formation. Therefore, PIP5KIgamma87's PIP(2) pool that supports GPCR-mediated Ca(2+) signaling is functionally compartmentalized from those generated by the other PIP5KIs.

    Funded by: NIGMS NIH HHS: GM21681, P50 GM021681

    The Journal of cell biology 2004;167;6;1005-10

  • The DNA sequence and biology of human chromosome 19.

    Grimwood J, Gordon LA, Olsen A, Terry A, Schmutz J, Lamerdin J, Hellsten U, Goodstein D, Couronne O, Tran-Gyamfi M, Aerts A, Altherr M, Ashworth L, Bajorek E, Black S, Branscomb E, Caenepeel S, Carrano A, Caoile C, Chan YM, Christensen M, Cleland CA, Copeland A, Dalin E, Dehal P, Denys M, Detter JC, Escobar J, Flowers D, Fotopulos D, Garcia C, Georgescu AM, Glavina T, Gomez M, Gonzales E, Groza M, Hammon N, Hawkins T, Haydu L, Ho I, Huang W, Israni S, Jett J, Kadner K, Kimball H, Kobayashi A, Larionov V, Leem SH, Lopez F, Lou Y, Lowry S, Malfatti S, Martinez D, McCready P, Medina C, Morgan J, Nelson K, Nolan M, Ovcharenko I, Pitluck S, Pollard M, Popkie AP, Predki P, Quan G, Ramirez L, Rash S, Retterer J, Rodriguez A, Rogers S, Salamov A, Salazar A, She X, Smith D, Slezak T, Solovyev V, Thayer N, Tice H, Tsai M, Ustaszewska A, Vo N, Wagner M, Wheeler J, Wu K, Xie G, Yang J, Dubchak I, Furey TS, DeJong P, Dickson M, Gordon D, Eichler EE, Pennacchio LA, Richardson P, Stubbs L, Rokhsar DS, Myers RM, Rubin EM and Lucas SM

    Stanford Human Genome Center, Department of Genetics, Stanford University School of Medicine, 975 California Avenue, Palo Alto, California 94304, USA. jane@shgc.stanford.edu

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high G + C content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in mendelian disorders, including familial hypercholesterolaemia and insulin-resistant diabetes. Nearly one-quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

    Nature 2004;428;6982;529-35

  • Btk-dependent regulation of phosphoinositide synthesis.

    Carpenter CL

    Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, HIM Building, Room 1026, 330 Brookline Avenue, Boston, MA 02215, U.S.A. ccarpent@bidmc.harvard.edu

    Activation of the BCR (B cell antigen receptor) stimulates the production of both PtdIns(3,4,5) P3 and Ins(1,4,5) P3. PtdIns(3,4,5) P3 and Ins(1,4,5) P3 are generated from a common substrate, PtdIns(4,5) P2. In some systems, continuous PtdIns(4,5) P2 synthesis is necessary for maximal Ins(1,4,5) P3 production, but whether this is true for the BCR, and whether PtdIns(4,5) P2 synthesis is regulated following BCR activation, are not known. We found that Btk (Bruton's tyrosine kinase), a member of the Tec family of cytoplasmic protein tyrosine kinases, is constitutively associated with PIP5Ks (phosphatidylinositol 4-phosphate 5-kinases), the enzymes that synthesize PtdIns(4,5) P2. Btk functions as a shuttle to bring PIP5K to the plasma membrane as a means of stimulating PtdIns(4,5) P2 synthesis. The Btk-PIP5K complex appears to localize to lipid rafts. This complex provides a novel shuttling mechanism that allows Btk to regulate the production of the substrate required by both its upstream activator phosphoinositide 3-kinase and its downstream target phospholipase Cgamma2.

    Funded by: NIGMS NIH HHS: GM 53590

    Biochemical Society transactions 2004;32;Pt 2;326-9

  • Identification and characterization of a phosphoinositide phosphate kinase homolog.

    Chang JD, Field SJ, Rameh LE, Carpenter CL and Cantley LC

    Beth Israel Deaconess Medical Center, Divisions of Signal Transduction, Cardiovascular Medicine, and Hematology-Oncology, Boston, Massachusetts 02215, USA. jchang@bidmc.harvard.edu

    Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) plays a central role in regulating the actin cytoskeleton as a substrate for phosphoinositide 3-kinase and phospholipase C as well as by binding directly to proteins that control the processes of actin monomer sequestration, filament severing, capping, nucleation, cross-linking, and bundling (Ma, L., Cantley, L. C., Janmey, P. A., and Kirschner, M. W. (1998) J. Cell Biol. 140, 1125-1136; Hinchliffe, K. (2000) Curr. Biol. 10, R104-R1051). Three related phosphatidylinositol 4-phosphate 5-kinases (PI(4)P 5-kinases) have been identified in mammalian cells (types Ialpha, Ibeta, and Igamma) and appear to play distinct roles in actin remodeling. Here we have identified a fourth member of this family by searching the human genome and EST data bases. This new protein, which we have designated phosphatidylinositol phosphate kinase homolog (PIPKH), is expressed at relatively high levels in brain and testis. Immunoprecipitates of PIPKH expressed in mammalian cells contain PI(4)P 5-kinase activity, but this activity is not affected by mutations in residues that inactivate other type I PI(4)P 5-kinases. We show that the PI(4)P 5-kinase activity in PIPKH immunoprecipitates can be explained by the ability of PIPKH to heterodimerize with other type I PI(4)P 5-kinases. Transfection of 293t cells with PIPKH resulted in >8-fold increase in total phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P(3)) without a significant net increase in total PI(4,5)P(2). When coexpressed with PIPKH, green fluorescent protein (GFP) fusion construct of the pleckstrin homology domain from Bruton's tyrosine kinase (GFP-BTK-PH) localized in intracellular vesicular structures, suggesting an unusual intracellular site of PI(3,4,5)P(3) production. Finally, expression of PIPKH induced the reorganization of actin from predominantly stress fibers to predominantly foci and comets similar to those observed previously in cells infected with the intracellular pathogen Listeria or transfected with recombinant PIPKIalpha. These results suggest that PIPKH acts as a scaffold to localize and regulate type I PI(4)P 5-kinases and the synthesis of PI(3,4,5)P(3).

    Funded by: NHLBI NIH HHS: HL03313; NIGMS NIH HHS: GM36624, GM54389

    The Journal of biological chemistry 2004;279;12;11672-9

  • Branches of the B cell antigen receptor pathway are directed by protein conduits Bam32 and Carma1.

    Niiro H and Clark EA

    Department of Microbiology, University of Washington, Seattle, WA 98195, USA.

    Adaptor proteins act as conduits to channel upstream signals into downstream effector branches. Two B cell-associated adaptors, Bam32 and Carma1, regulate the ERK, JNK, and NF-kappaB branches of the BCR signaling pathway. Recent studies of Bam32-/- and Carma1-/- mice suggest that each adaptor controls a distinct conduit regulating either only proliferation (Bam32) or both the proliferation and survival of B cells (Carma1).

    Funded by: NIAID NIH HHS: AI44250, AI45088

    Immunity 2003;19;5;637-40

  • ARF6 stimulates clathrin/AP-2 recruitment to synaptic membranes by activating phosphatidylinositol phosphate kinase type Igamma.

    Krauss M, Kinuta M, Wenk MR, De Camilli P, Takei K and Haucke V

    Zentrum für Biochemie und Molekulare Zellbiologie, Dept. of Biochemistry II, University of Göttingen, Humboldtallee 23, Göttingen D-37073, Germany.

    Clathrin-mediated endocytosis of synaptic vesicle membranes involves the recruitment of clathrin and AP-2 adaptor complexes to the presynaptic plasma membrane. Phosphoinositides have been implicated in nucleating coat assembly by directly binding to several endocytotic proteins including AP-2 and AP180. Here, we show that the stimulatory effect of ATP and GTPgammaS on clathrin coat recruitment is mediated at least in part by increased levels of PIP2. We also provide evidence for a role of ADP-ribosylation factor 6 (ARF6) via direct stimulation of a synaptically enriched phosphatidylinositol 4-phosphate 5-kinase type Igamma (PIPKIgamma), in this effect. These data suggest a model according to which activation of PIPKIgamma by ARF6-GTP facilitates clathrin-coated pit assembly at the synapse.

    Funded by: NIDDK NIH HHS: DK 54913; NINDS NIH HHS: NS 36251, R01 NS036251, R37 NS036251

    The Journal of cell biology 2003;162;1;113-24

  • Membrane ruffling requires coordination between type Ialpha phosphatidylinositol phosphate kinase and Rac signaling.

    Doughman RL, Firestone AJ, Wojtasiak ML, Bunce MW and Anderson RA

    Molecular and Cellular Pharmacology Program, Department of Pharmacology, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.

    Membrane ruffle formation requires remodeling of cortical actin filaments, a process dependent upon the small G-protein Rac. Growth factors stimulate actin remodeling and membrane ruffling by integration of signaling pathways that regulate actin-binding proteins. Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates the activity of many actin-binding proteins and is produced by the type I phosphatidylinositol phosphate kinases (PIPKIs). Here we show in MG-63 cells that only the PIPKIalpha isoform is localized to platelet-derived growth factor (PDGF)-induced membrane ruffles. Further, expression of kinase dead PIPKIalpha, which acts as a dominant negative mutant, blocked membrane ruffling, suggesting that PIPKIalpha and PIP2 participate in ruffling. To explore this, PIPKIalpha was overexpressed in serum-starved cells and stimulated with PDGF. In serum-starved cells, PIPKIalpha expression did not stimulate actin remodeling, but when these cells were stimulated with PDGF, actin rapidly reorganized into foci but not membrane ruffles. PIPKIalpha-mediated formation of actin foci was independent of both Rac1 and phosphatidylinositol 3-kinase activities. Significantly, coexpression of dominant active Rac1 with PIPKIalpha in PDGF-stimulated cells resulted in membrane ruffling. The PDGF- and Rac1-stimulated ruffling was inhibited by expression of kinase-dead PIPKIalpha. Combined, these data support a model where the localized production of PIP2 by PIPKIalpha is necessary for actin remodeling, whereas formation of membrane ruffles required Rac signaling.

    Funded by: NIGMS NIH HHS: GM-144-KW76

    The Journal of biological chemistry 2003;278;25;23036-45

  • Recruitment and regulation of phosphatidylinositol phosphate kinase type 1 gamma by the FERM domain of talin.

    Di Paolo G, Pellegrini L, Letinic K, Cestra G, Zoncu R, Voronov S, Chang S, Guo J, Wenk MR and De Camilli P

    Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.

    Membrane phosphoinositides control a variety of cellular processes through the recruitment and/or regulation of cytosolic proteins. One mechanism ensuring spatial specificity in phosphoinositide signalling is the targeting of enzymes that mediate their metabolism to specific subcellular sites. Phosphatidylinositol phosphate kinase type 1 gamma (PtdInsPKI gamma) is a phosphatidylinositol-4-phosphate 5-kinase that is expressed at high levels in brain, and is concentrated at synapses. Here we show that the predominant brain splice variant of PtdInsPKI gamma (PtdInsPKI gamma-90) binds, by means of a short carboxy-terminal peptide, to the FERM domain of talin, and is strongly activated by this interaction. Talin, a principal component of focal adhesion plaques, is also present at synapses. PtdInsPKI gamma-90 is expressed in non-neuronal cells, albeit at much lower levels than in neurons, and is concentrated at focal adhesion plaques, where phosphatidylinositol-4,5-bisphosphate has an important regulatory role. Overexpression of PtdInsPKI gamma-90, or expression of its C-terminal domain, disrupts focal adhesion plaques, probably by local disruption of normal phosphoinositide balance. These findings define an interaction that has a regulatory role in cell adhesion and suggest new similarities between molecular interactions underlying synaptic junctions and general mechanisms of cell adhesion.

    Funded by: Telethon: 485/B

    Nature 2002;420;6911;85-9

  • Type I gamma phosphatidylinositol phosphate kinase targets and regulates focal adhesions.

    Ling K, Doughman RL, Firestone AJ, Bunce MW and Anderson RA

    Department of Pharmacology, Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison, 1300 University Avenue, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.

    The ability of cells to form cell contacts, adhere to the extracellular matrix, change morphology, and migrate is essential for development, wound healing, metastasis, cell survival and the immune response. These events depend on the binding of integrin to the extracellular matrix, and assembly of focal adhesions, which are complexes comprising scaffolding and signalling proteins organized by adhesion to the extracellular matrix. Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) regulates interactions between these proteins, including the interaction of vinculin with actin and talin. The binding of talin to beta-integrin is strengthened by PtdIns(4,5)P(2), suggesting that the basis of focal adhesion assembly is regulated by this lipid mediator. Here we show that the type I phosphatidylinositol phosphate kinase isoform-gamma 661 (PIPKI gamma 661), an enzyme that makes PtdIns(4,5)P(2), is targeted to focal adhesions by an association with talin. PIPKI gamma 661 is tyrosine phosphorylated by focal adhesion associated kinase signalling, increasing both the activity of phosphatidylinositol phosphate kinase and its association with talin. This defines a mechanism for spatial generation of PtdIns(4,5)P(2) at focal adhesions.

    Nature 2002;420;6911;89-93

  • PIP kinase Igamma is the major PI(4,5)P(2) synthesizing enzyme at the synapse.

    Wenk MR, Pellegrini L, Klenchin VA, Di Paolo G, Chang S, Daniell L, Arioka M, Martin TF and De Camilli P

    Howard Hughes Medical Institute and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA.

    Disruption of the presynaptically enriched polyphosphoinositide phosphatase synaptojanin 1 leads to an increase of clathrin-coated intermediates and of polymerized actin at endocytic zones of nerve terminals. These changes correlate with elevated levels of PI(4,5)P(2) in neurons. We report that phosphatidylinositol phosphate kinase type Igamma (PIPKIgamma), a major brain PI(4)P 5-kinase, is concentrated at synapses. Synaptojanin 1 and PIPKIgamma antagonize each other in the recruitment of clathrin coats to lipid membranes. Like synaptojanin 1 and other proteins involved in endocytosis, PIPKIgamma undergoes stimulation-dependent dephosphorylation. These results implicate PIPKIgamma in the synthesis of a PI(4,5)P(2) pool that acts as a positive regulator of clathrin coat recruitment and actin function at the synapse.

    Neuron 2001;32;1;79-88

  • Interactions of the low density lipoprotein receptor gene family with cytosolic adaptor and scaffold proteins suggest diverse biological functions in cellular communication and signal transduction.

    Gotthardt M, Trommsdorff M, Nevitt MF, Shelton J, Richardson JA, Stockinger W, Nimpf J and Herz J

    Department of Molecular Genetics and Pathology, University of Texas Southwestern Medical Center, Dallas 75390-9046, USA.

    The members of the low density lipoprotein (LDL) receptor gene family bind a broad spectrum of extracellular ligands. Traditionally, they had been regarded as mere cargo receptors that promote the endocytosis and lysosomal delivery of these ligands. However, recent genetic experiments in mice have revealed critical functions for two LDL receptor family members, the very low density lipoprotein receptor and the apoE receptor-2, in the transmission of extracellular signals and the activation of intracellular tyrosine kinases. This process regulates neuronal migration and is crucial for brain development. Signaling through these receptors requires the interaction of their cytoplasmic tails with the intracellular adaptor protein Disabled-1 (DAB1). Here, we identify an extended set of cytoplasmic proteins that might also participate in signal transmission by the LDL receptor gene family. Most of these novel proteins are adaptor or scaffold proteins that contain PID or PDZ domains and function in the regulation of mitogen-activated protein kinases, cell adhesion, vesicle trafficking, or neurotransmission. We show that binding of DAB1 interferes with receptor internalization suggesting a mechanism by which signaling through this class of receptors might be regulated. Taken together, these findings imply much broader physiological functions for the LDL receptor family than had previously been appreciated. They form the basis for the elucidation of the molecular pathways by which cells respond to the diversity of ligands that bind to these multifunctional receptors on the cell surface.

    Funded by: NHLBI NIH HHS: HL20948, HL63762, R37 HL063762

    The Journal of biological chemistry 2000;275;33;25616-24

  • Type I phosphatidylinositol-4-phosphate 5-kinases. Cloning of the third isoform and deletion/substitution analysis of members of this novel lipid kinase family.

    Ishihara H, Shibasaki Y, Kizuki N, Wada T, Yazaki Y, Asano T and Oka Y

    Third Department of Internal Medicine, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan. ishihara-tky@umin.u-tokyo.ac.jp

    Type I phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinases (PIP5K) catalyze the synthesis of phosphatidylinositol 4, 5-bisphosphate, an essential lipid molecule in various cellular processes. Here, we report the cloning of the third member (PIP5Kgamma) and the characterization of members of the type I PIP5K family. Type I PIP5Kgamma has two alternative splicing forms, migrating at 87 and 90 kDa on SDS-polyacrylamide gel electrophoresis. The amino acid sequence of the central portion of this isoform shows approximately 80% identity with those of the alpha and beta isoforms. Northern blot analysis revealed that the gamma isoform is highly expressed in the brain, lung, and kidneys. Among three isoforms, the beta isoform has the greatest Vmax value for the PtdIns(4)P kinase activity and the gamma isoform is most markedly stimulated by phosphatidic acid. By analyzing deletion mutants of the three isoforms, the minimal kinase core sequence of these isoforms were determined as an approximately 380-amino acid region. In addition, carboxyl-terminal regions of the beta and gamma isoforms were found to confer the greatest Vmax value and the highest phosphatidic acid sensitivity, respectively. It was also discovered that lysine 138 in the putative ATP binding motif of the alpha isoform is essential for the PtdIns(4)P kinase activity. As was the case with the alpha isoform reported previously (Shibasaki, Y., Ishihara, H., Kizuki, N., Asano, T., Oka, Y., Yazaki, Y. (1997) J. Biol. Chem. 272, 7578-7581), overexpression of either the beta or the gamma isoform induced an increase in short actin fibers and a decrease in actin stress fibers in COS7 cells. Surprisingly, a kinase-deficient substitution mutant also induced an abnormal actin polymerization, suggesting a role of PIP5Ks via structural interactions with other molecules.

    The Journal of biological chemistry 1998;273;15;8741-8

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

    Nagase T, Ishikawa K, Miyajima N, Tanaka A, Kotani H, Nomura N and Ohara O

    Kazusa DNA Research Institute, Kisarazu, Chiba, Japan.

    As an extension of a series of projects for sequencing human cDNA clones derived from relatively long transcripts, we herein report the entire sequences of 100 newly determined cDNA clones with the potential of coding for large proteins in vitro. The cDNA clones were isolated from size-fractionated human brain cDNA libraries with insert sizes between 4.5 and 8.3 kb. The sequencing of these clones revealed that the average size of the cDNA inserts and of their open reading frames was 5.3 kb and 2.8 kb (930 amino acid residues), respectively. Homology search against public databases indicated that the predicted coding sequences of 86 clones exhibited significant similarities to known genes; 51 of them (59%) were related to those for cell signaling/communication, nucleic acid management, and cell structure/motility. All the clones characterized in this study are accompanied by their expression profiles in 14 human tissues examined by reverse transcription-coupled polymerase chain reaction and the chromosomal mapping data.

    DNA research : an international journal for rapid publication of reports on genes and genomes 1998;5;1;31-9

Gene lists (3)

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
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
© 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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