PIK3CA - Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform - human protein (Function)
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PIK3CA »  Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform   [ EC ]  (PI3Kalpha)
Protein also known as:  Phosphatidylinositol 4,5-bisphosphate 3-kinase 110 kDa catalytic subunit alpha (p110alpha).
Gene name:  PIK3CA
Family name: PI3/PI4-kinase
Entry whose protein(s) existence is based on evidence at protein level
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Phosphoinositide-3-kinase (PI3K) that phosphorylates PtdIns (Phosphatidylinositol), PtdIns4P (Phosphatidylinositol 4-phosphate) and PtdIns(4,5)P2 (Phosphatidylinositol 4,5-bisphosphate) to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3). PIP3 plays a key role by recruiting PH domain-containing proteins to the membrane, including AKT1 and PDPK1, activating signaling cascades involved in cell growth, survival, proliferation, motility and morphology. Participates in cellular signaling in response to various growth factors. Involved in the activation of AKT1 upon stimulation by receptor tyrosine kinases ligands such as EGF, insulin, IGF1, VEGFA and PDGF. Involved in signaling via insulin-receptor substrate (IRS) proteins. Essential in endothelial cell migration during vascular development through VEGFA signaling, possibly by regulating RhoA activity. Required for lymphatic vasculature development, possibly by binding to RAS and by activation by EGF and FGF2, but not by PDGF. Regulates invadopodia formation in breast cancer cells through the PDPK1-AKT1 pathway. Participates in cardiomyogenesis in embryonic stem cells through a AKT1 pathway. Participates in vasculogenesis in embryonic stem cells through PDK1 and protein kinase C pathway. Has also serine-protein kinase activity: phosphorylates PIK3R1 (p85alpha regulatory subunit), EIF4EBP1 and HRAS.  
  • CuratedUniProtKB
GO molecular function 
1-phosphatidylinositol-3-kinase activitydefinition[GO:0016303]  
  • IDAUniProtKB
1-phosphatidylinositol-4-phosphate 3-kinase activitydefinition[GO:0035005] silver  
  • IBARefGenome
ATP bindingdefinition[GO:0005524]  
  • IEAUniProtKB KW
Insulin receptor substrate bindingdefinition[GO:0043560] silver  
  • IEAOrtholog Compara
Phosphatidylinositol 3-kinase activitydefinition[GO:0035004]  
  • TASUniProtKB
  • ISSOrtholog Curator
Protein bindingdefinition[GO:0005515]  
  • IPIIntAct
  • IPIUniProtKB
Protein kinase activator activitydefinition[GO:0030295] silver  
  • IEAOrtholog Compara
Protein serine/threonine kinase activitydefinition[GO:0004674]  
  • IEAUniProtKB KW
GO biological process 
  • IEAUniProtKB KW
Cardiac muscle contractiondefinition[GO:0060048]  
  • TASUniProtKB
Endothelial cell migrationdefinition[GO:0043542]  
  • TASUniProtKB
Glucose metabolic processdefinition[GO:0006006] silver  
  • IEAOrtholog Compara
Hypomethylation of CpG islanddefinition[GO:0044029] silver  
  • IEAOrtholog Compara
Insulin receptor signaling pathway via phosphatidylinositol 3-kinasedefinition[GO:0038028]  
  • TASUniProtKB
Negative regulation of anoikisdefinition[GO:2000811]  
  • IMPUniProtKB
Negative regulation of fibroblast apoptotic processdefinition[GO:2000270] silver  
  • IEAOrtholog Compara
Negative regulation of neuron apoptotic processdefinition[GO:0043524] silver  
  • IEAOrtholog Compara
Phosphatidylinositol phosphorylationdefinition[GO:0046854]  
  • ISSOrtholog Curator
Phosphatidylinositol-3-phosphate biosynthetic processdefinition[GO:0036092]  
  • IEAOrtholog Compara
Platelet activationdefinition[GO:0030168]  
  • TASUniProtKB
Positive regulation of peptidyl-serine phosphorylationdefinition[GO:0033138] silver  
  • IEAOrtholog Compara
Positive regulation of protein kinase activitydefinition[GO:0045860] silver  
  • IEAOrtholog Compara
Protein kinase B signalingdefinition[GO:0043491] silver  
  • IEAOrtholog Compara
Protein phosphorylationdefinition[GO:0006468] silver  
  • IEAOrtholog Compara
Regulation of genetic imprintingdefinition[GO:2000653] silver  
  • IEAOrtholog Compara
Regulation of multicellular organism growthdefinition[GO:0040014] silver  
  • IEAOrtholog Compara
Vasculature developmentdefinition[GO:0001944]  
  • TASUniProtKB
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reactions
EC ATP + 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate ADP + 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate.  
  • CuratedUniProtKB
EC ATP + a protein ADP + a phosphoprotein.  
  • CuratedUniProtKB
More information is available from:
According to KEGG, this protein belongs to the following pathways:
Acute myeloid leukemia  hsa05221+5290  
Aldosterone-regulated sodium reabsorption  hsa04960+5290  
Amoebiasis  hsa05146+5290  
Apoptosis  hsa04210+5290  
B cell receptor signaling pathway  hsa04662+5290  
Bacterial invasion of epithelial cells  hsa05100+5290  
Carbohydrate digestion and absorption  hsa04973+5290  
Chagas disease (American trypanosomiasis)  hsa05142+5290  
Chemokine signaling pathway  hsa04062+5290  
Cholinergic synapse  hsa04725+5290  
Colorectal cancer  hsa05210+5290  
Endometrial cancer  hsa05213+5290  
ErbB signaling pathway  hsa04012+5290  
Fc epsilon RI signaling pathway  hsa04664+5290  
Fc gamma R-mediated phagocytosis  hsa04666+5290  
Focal adhesion  hsa04510+5290  
Glioma  hsa05214+5290  
Hepatitis C  hsa05160+5290  
HTLV-I infection  hsa05166+5290  
Influenza A  hsa05164+5290  
Inositol phosphate metabolism  hsa00562+5290  
Insulin signaling pathway  hsa04910+5290  
Jak-STAT signaling pathway  hsa04630+5290  
Leukocyte transendothelial migration  hsa04670+5290  
Measles  hsa05162+5290  
Melanoma  hsa05218+5290  
mTOR signaling pathway  hsa04150+5290  
Natural killer cell mediated cytotoxicity  hsa04650+5290  
Neurotrophin signaling pathway  hsa04722+5290  
Non-small cell lung cancer  hsa05223+5290  
Osteoclast differentiation  hsa04380+5290  
Pancreatic cancer  hsa05212+5290  
Pathways in cancer  hsa05200+5290  
Phosphatidylinositol signaling system  hsa04070+5290  
Progesterone-mediated oocyte maturation  hsa04914+5290  
Prostate cancer  hsa05215+5290  
Regulation of actin cytoskeleton  hsa04810+5290  
Renal cell carcinoma  hsa05211+5290  
Small cell lung cancer  hsa05222+5290  
T cell receptor signaling pathway  hsa04660+5290  
Toll-like receptor signaling pathway  hsa04620+5290  
Toxoplasmosis  hsa05145+5290  
Type II diabetes mellitus  hsa04930+5290  
VEGF signaling pathway  hsa04370+5290  
According to Reactome, this protein belongs to the following pathways:
CD28 dependent PI3K/Akt signaling  REACT_19358  
Constitutive PI3K/AKT Signaling in Cancer  REACT_147727  
Costimulation by the CD28 family  REACT_19344  
DAP12 signaling  REACT_147814  
Downstream signal transduction  REACT_17025  
Downstream TCR signaling  REACT_12555  
G alpha (12/13) signalling events  REACT_18407  
G alpha (q) signalling events  REACT_18283  
GAB1 signalosome  REACT_12578  
GPVI-mediated activation cascade  REACT_1695  
Interleukin receptor SHC signaling  REACT_23891  
Interleukin-3, 5 and GM-CSF signaling  REACT_23837  
Nephrin interactions  REACT_23832  
PI-3K cascade  REACT_21270  
PI3K Cascade  REACT_976  
PI3K events in ERBB2 signaling  REACT_116008  
PI3K events in ERBB4 signaling  REACT_115961  
PI3K/AKT activation  REACT_12464  
PIP3 activates AKT signaling  REACT_75829  
Regulation of signaling by CBL  REACT_23787  
Role of LAT2/NTAL/LAB on calcium mobilization  REACT_163769  
Role of phospholipids in phagocytosis  REACT_160158  
Signaling by constitutively active EGFR  REACT_115852  
Signaling by FGFR mutants  REACT_121398  
Signaling by FGFR1 fusion mutants  REACT_121141  
Signaling by SCF-KIT  REACT_111040  
Synthesis of PIPs at the plasma membrane  REACT_121025  
Tie2 Signaling  REACT_12621  
More information is available from:
The avian sarcoma virus 16 genome encodes an oncogene derived from PIK3CA (PubMed18418043).  
  • CuratedUniProtKB


Biological process 
Angiogenesis  definition   [KW-0037]
Molecular function 
Kinase  definition   [KW-0418]
Serine/threonine-protein kinase  definition   [KW-0723]
Transferase  definition   [KW-0808]
Technical term 
Reference proteome  definition   [KW-1185]

Further external links

GeneWiki: P110%CE%B1
GenomeRNAi: 5290
PRO: PR:P42336