PIK3R1 Binds to activated (phosphorylated) protein-Tyr kinases, through its SH2 domain, and acts as an adapter, mediating the association of the p110 catalytic unit to the plasma membrane. Necessary for the insulin-stimulated increase in glucose uptake and glycogen synthesis in insulin-sensitive tissues. Plays an important role in signaling in response to FGFR1, FGFR2, FGFR3, FGFR4, KITLG/SCF, KIT, PDGFRA and PDGFRB. Likewise, plays a role in ITGB2 signaling. Modulates the cellular response to ER stress by promoting nuclear translocation of XBP1 isoform 2 in a ER stress- and/or insulin-dependent manner during metabolic overloading in the liver and hence plays a role in glucose tolerance improvement. Belongs to the PI3K p85 subunit family. Isoform 2 is expressed in skeletal muscle and brain, and at lower levels in kidney and cardiac muscle. Isoform 2 and isoform 4 are present in skeletal muscle (at protein level). 5 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Kinase, lipid; Motility/polarity/chemotaxis
Chromosomal Location of rat Ortholog: 2q12
Cellular Component:  cell-cell junction; cis-Golgi network; cytoplasm; cytosol; membrane; neuron projection; nucleus; perinuclear endoplasmic reticulum membrane; phosphatidylinositol 3-kinase complex; phosphatidylinositol 3-kinase complex, class IA; plasma membrane; protein-containing complex
Molecular Function:  1-phosphatidylinositol-3-kinase activity; 1-phosphatidylinositol-3-kinase regulator activity; ATPase binding; calmodulin binding; ErbB-3 class receptor binding; estrogen receptor binding; insulin binding; insulin receptor binding; insulin receptor substrate binding; insulin-like growth factor receptor binding; neurotrophin TRKA receptor binding; phosphatidylinositol 3-kinase regulator activity; phosphatidylinositol 3-kinase regulatory subunit binding; phosphoprotein binding; phosphotyrosine residue binding; platelet-derived growth factor receptor binding; protein binding; protein C-terminus binding; protein domain specific binding; protein heterodimerization activity; protein kinase binding; protein phosphatase binding; receptor tyrosine kinase binding; signaling receptor binding; transcription factor binding; ubiquitin protein ligase binding
Biological Process:  aging; B cell differentiation; cellular glucose homeostasis; cellular response to fatty acid; cellular response to insulin stimulus; cellular response to UV; extrinsic apoptotic signaling pathway via death domain receptors; glucose metabolic process; growth hormone receptor signaling pathway; insulin receptor signaling pathway; insulin-like growth factor receptor signaling pathway; intrinsic apoptotic signaling pathway in response to DNA damage; negative regulation of apoptotic process; negative regulation of blood pressure; negative regulation of cell adhesion; negative regulation of cell-cell adhesion; negative regulation of cell-matrix adhesion; negative regulation of heart rate; negative regulation of muscle cell apoptotic process; negative regulation of osteoclast differentiation; negative regulation of proteolysis; negative regulation of smooth muscle cell proliferation; phosphatidylinositol 3-kinase signaling; phosphatidylinositol phosphorylation; phosphatidylinositol-3-phosphate biosynthetic process; positive regulation of cell migration; positive regulation of endoplasmic reticulum unfolded protein response; positive regulation of gene expression; positive regulation of myoblast differentiation; positive regulation of protein import into nucleus; positive regulation of protein phosphorylation; positive regulation of RNA splicing; positive regulation of transcription by RNA polymerase II; positive regulation of tumor necrosis factor production; protein import into nucleus; protein phosphorylation; protein stabilization; protein transport; regulation of insulin receptor signaling pathway; regulation of phosphatidylinositol 3-kinase activity; regulation of protein localization to plasma membrane; regulation of stress fiber assembly; response to amino acid; response to cAMP; response to dexamethasone; response to drug; response to endoplasmic reticulum stress; response to estradiol; response to ethanol; response to fatty acid; response to fructose; response to glucocorticoid; response to growth factor; response to insulin; response to iron(II) ion; response to nutrient; response to progesterone; response to testosterone; response to yeast
Reference #:  Q63787 (UniProtKB)
Alt. Names/Synonyms: P85A; Phosphatidylinositol 3-kinase 85 kDa regulatory subunit alpha; Phosphatidylinositol 3-kinase regulatory subunit alpha; phosphatidylinositol 3-kinase, regulatory subunit, polypeptide 1 (p85 alpha); Phosphoinositide 3-kinase p85 (other splicing variants: p55 and p50); Phosphoinositide 3-kinase, regulatory subunit, polypeptide 1 (p85 alpha); phosphoinositide-3-kinase, regulatory subunit 1 (alpha); PI3-kinase p85 subunit alpha; PI3-kinase regulatory subunit alpha; PI3-kinase subunit p85-alpha; PI3K regulatory subunit alpha; PI3KA; Pik3r1; ptdIns-3-kinase p85-alpha; PtdIns-3-kinase regulatory subunit alpha; PtdIns-3-kinase regulatory subunit p85-alpha
Gene Symbols: Pik3r1
Molecular weight: 83,531 Da
Basal Isoelectric point: 5.9  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, siRNAs or Recombinant Proteins from Cell Signaling Technology® Total Proteins
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Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  Reactome  |  BioGPS  |  Pfam  |  RCSB PDB  |  Phospho3D  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene