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PIK3R1 regulatory subunit of phosphoinositide-3-kinase. Mediates binding to a subset of tyrosine-phosphorylated proteins through its SH2 domain. Acts as an adapter, mediating the association of the p110 catalytic unit of the alpha, beta and delta enzymes to the plasma membrane, where p110 phosphorylates inositol lipids. May play an additional role in the regulation of the actin cytoskeleton. Necessary for the insulin-stimulated increase in glucose uptake and glycogen synthesis in insulin-sensitive tissues. Its SH2 domains interacts with the YTHM motif of phosphorylated INSR in vitro. Defects in PIK3R1 are a cause of severe insulin resistance. Four alternatively spliced isoforms have been described. Note: This description may include information from UniProtKB.
Protein type: Kinase, lipid; Motility/polarity/chemotaxis
Chromosomal Location of Human Ortholog: 5q13.1
Cellular Component: cytoplasm; cytosol; membrane; nucleus; phosphoinositide 3-kinase complex; plasma membrane
Molecular Function: 1-phosphatidylinositol-3-kinase activity; 1-phosphatidylinositol-3-kinase regulator activity; ErbB-3 class receptor binding; insulin binding; insulin receptor binding; insulin receptor substrate binding; insulin-like growth factor receptor binding; neurotrophin TRKA receptor binding; phosphatidylinositol-4,5-bisphosphate 3-kinase activity; phosphoinositide 3-kinase binding; phosphoinositide 3-kinase regulator activity; phosphotyrosine binding; protein binding; protein phosphatase binding; transcription factor binding; transmembrane receptor protein tyrosine kinase adaptor protein activity
Biological Process: axon guidance; cell glucose homeostasis; cellular response to insulin stimulus; epidermal growth factor receptor signaling pathway; insulin receptor signaling pathway; insulin-like growth factor receptor signaling pathway; leukocyte migration; negative regulation of apoptosis; phosphatidylinositol biosynthetic process; phosphoinositide 3-kinase cascade; phosphoinositide phosphorylation; phosphoinositide-mediated signaling; platelet activation; positive regulation of glucose import; positive regulation of RNA splicing; positive regulation of transcription factor import into nucleus; positive regulation of transcription from RNA polymerase II promoter; protein stabilization; regulation of phosphoinositide 3-kinase activity; regulation of phosphoinositide 3-kinase cascade; T cell costimulation; T cell receptor signaling pathway; vascular endothelial growth factor receptor signaling pathway
Disease: Agammaglobulinemia 7, Autosomal Recessive; Immunodeficiency 36; Short Syndrome
Reference #:  P27986 (UniProtKB)
Alt. Names/Synonyms: GRB1; p85; p85-ALPHA; P85A; Phosphatidylinositol 3-kinase 85 kDa regulatory subunit alpha; Phosphatidylinositol 3-kinase regulatory subunit alpha; phosphatidylinositol 3-kinase, regulatory subunit, polypeptide 1 (p85 alpha); phosphatidylinositol 3-kinase, regulatory, 1; phosphatidylinositol 3-kinase-associated p-85 alpha; phosphoinositide-3-kinase, regulatory subunit 1 (alpha); PI3-kinase regulatory subunit alpha; PI3-kinase subunit p85-alpha; PI3K regulatory subunit alpha; PIK3R1; PtdIns-3-kinase regulatory subunit alpha; PtdIns-3-kinase regulatory subunit p85-alpha
Gene Symbols: PIK3R1
Molecular weight: 83,598 Da
Basal Isoelectric point: 5.84  Predict pI for various phosphorylation states
CST Pathways:  Actin Dynamics  |  Adherens Junction Dynamics  |  AMPK Signaling  |  Angiogenesis  |  Apoptosis Regulation  |  B Cell Receptor Signaling  |  ErbB/HER Signaling  |  ESC Pluripotency and Differentiation  |  Growth And Differentiation Control by MAPKs  |  IL6 Signaling  |  Inhibition of Apoptosis  |  Insulin Receptor Signaling  |  Microtubule Dynamics  |  Mitochondrial Control of Apoptosis  |  mTOR Signaling  |  NF-kB Signaling  |  PI3K/Akt Signaling  |  Protein Kinase C Signaling  |  SAPK/JNK Signaling Cascades  |  T Cell Receptor Signaling  |  TGF-ß Signaling  |  Translation: eIF4E and p70S6K  |  Warburg Effect
Protein-Specific Antibodies or siRNAs from Cell Signaling Technology® Total Proteins
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