PIK3CB

This gene encodes an isoform of the catalytic subunit of phosphoinositide 3-kinase (PI3K). These kinases are important in signaling pathways involving receptors on the outer membrane of eukaryotic cells and are named for their catalytic subunit. The encoded protein is the catalytic subunit for PI3Kbeta (PI3KB). PI3KB has been shown to be part of the activation pathway in neutrophils which have bound immune complexes at sites of injury or infection. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2011]

Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Beta

Phosphoinositide-3-kinase (PI3K) phosphorylates phosphatidylinositol derivatives at position 3 of the inositol ring to produce 3-phosphoinositides (PubMed:15135396).
Uses ATP and PtdIns(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) to generate phosphatidylinositol 3,4,5-trisphosphate (PIP3) (PubMed:15135396).
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. Involved in the activation of AKT1 upon stimulation by G-protein coupled receptors (GPCRs) ligands such as CXCL12, sphingosine 1-phosphate, and lysophosphatidic acid. May also act downstream receptor tyrosine kinases. Required in different signaling pathways for stable platelet adhesion and aggregation. Plays a role in platelet activation signaling triggered by GPCRs, alpha-IIb/beta-3 integrins (ITGA2B/ ITGB3) and ITAM (immunoreceptor tyrosine-based activation motif)-bearing receptors such as GP6. Regulates the strength of adhesion of ITGA2B/ ITGB3 activated receptors necessary for the cellular transmission of contractile forces. Required for platelet aggregation induced by F2 (thrombin) and thromboxane A2 (TXA2). Has a role in cell survival. May have a role in cell migration. Involved in the early stage of autophagosome formation. Modulates the intracellular level of PtdIns3P (phosphatidylinositol 3-phosphate) and activates PIK3C3 kinase activity. May act as a scaffold, independently of its lipid kinase activity to positively regulate autophagy. May have a role in insulin signaling as scaffolding protein in which the lipid kinase activity is not required. May have a kinase-independent function in regulating cell proliferation and in clathrin-mediated endocytosis. Mediator of oncogenic signal in cell lines lacking PTEN. The lipid kinase activity is necessary for its role in oncogenic transformation. Required for the growth of ERBB2 and RAS driven tumors. Has also a protein kinase activity showing autophosphorylation (PubMed:12502714).

Angiogenesis involved in wound healingIEA:Ensembl
AutophagyIEA:UniProtKB-KW
Cell migrationManual Assertion Based On ExperimentIBA:GO_Central
Cellular calcium ion homeostasisIEA:Ensembl
ChemotaxisManual Assertion Based On ExperimentTAS:ProtInc
Embryonic cleavageIEA:Ensembl
EndocytosisIEA:UniProtKB-KW
Endothelial cell proliferationIEA:Ensembl
G protein-coupled receptor signaling pathwayManual Assertion Based On ExperimentTAS:UniProtKB
Homophilic cell adhesion via plasma membrane adhesion moleculesIEA:Ensembl
Negative regulation of hypoxia-induced intrinsic apoptotic signaling pathwayIEA:Ensembl
Negative regulation of MAP kinase activityBy SimilarityISS:BHF-UCL
Negative regulation of protein kinase B signalingManual Assertion Based On ExperimentIGI:BHF-UCL
Negative regulation of sprouting angiogenesisManual Assertion Based On ExperimentIMP:BHF-UCL
Negative regulation of vascular endothelial growth factor signaling pathwayManual Assertion Based On ExperimentIGI:BHF-UCL
Phosphatidylinositol 3-kinase signalingManual Assertion Based On ExperimentIMP:BHF-UCL
Phosphatidylinositol phosphate biosynthetic processManual Assertion Based On ExperimentIBA:GO_Central
Phosphatidylinositol-3-phosphate biosynthetic processManual Assertion Based On ExperimentIBA:GO_Central
Phosphatidylinositol-mediated signalingManual Assertion Based On ExperimentIBA:GO_Central
PhosphorylationManual Assertion Based On ExperimentIDA:MGI
Platelet activationManual Assertion Based On ExperimentTAS:UniProtKB
Platelet aggregationManual Assertion Based On ExperimentTAS:UniProtKB
Positive regulation of autophagyManual Assertion Based On ExperimentTAS:UniProtKB
Positive regulation of endothelial cell migrationManual Assertion Based On ExperimentIGI:BHF-UCL
Positive regulation of gene expressionManual Assertion Based On ExperimentIMP:MGI
Positive regulation of neutrophil apoptotic processManual Assertion Based On ExperimentIMP:CAFA
Positive regulation of nitric-oxide synthase activityManual Assertion Based On ExperimentIMP:BHF-UCL
Positive regulation of protein kinase B signalingManual Assertion Based On ExperimentIMP:BHF-UCL
Positive regulation of Rac protein signal transductionManual Assertion Based On ExperimentIGI:BHF-UCL
Regulation of cell-matrix adhesionManual Assertion Based On ExperimentIMP:MGI
Regulation of clathrin-dependent endocytosisManual Assertion Based On ExperimentTAS:UniProtKB
Response to ischemiaBy SimilarityISS:BHF-UCL
Signal transduction1 PublicationNAS:ProtInc
Sphingosine-1-phosphate receptor signaling pathwayManual Assertion Based On ExperimentIMP:BHF-UCL
Transmembrane receptor protein tyrosine kinase signaling pathwayManual Assertion Based On ExperimentTAS:UniProtKB

Cytoplasm
Nucleus
Interaction with PIK3R2 is required for nuclear localization and export.

Autophosphorylation at Ser-1070 negatively regulates the phosphatidylinositol-4,5-bisphosphate 3-kinase activity.