Phosphoinositide 3 Kinase, P85 Alpha, P110 Beta, Active (PIK3R2) Active Protein

Phosphatidylinositol 3-kinase (PI3K) is a lipid kinase that phosphorylates phosphatidylinositol and similar compounds, creating second messengers important in growth signaling pathways. PI3K functions as a heterodimer of a regulatory and a catalytic subunit. The protein encoded by this gene is a regulatory component of PI3K. Two transcript variants, one protein coding and the other non-protein coding, have been found for this gene. [provided by RefSeq, Dec 2012]

PIK3R2: 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.

Protein type: Motility/polarity/chemotaxis; Kinase, lipid

Chromosomal Location of Human Ortholog: 19q13.2-q13.4

Cellular Component: cytosol; nucleus; phosphoinositide 3-kinase complex

Molecular Function: protein binding; protein heterodimerization activity; 1-phosphatidylinositol-3-kinase activity; phosphoinositide 3-kinase regulator activity; receptor tyrosine kinase binding; protein phosphatase binding

Biological Process: epidermal growth factor receptor signaling pathway; phosphoinositide 3-kinase cascade; fibroblast growth factor receptor signaling pathway; phosphoinositide-mediated signaling; nerve growth factor receptor signaling pathway; regulation of phosphoinositide 3-kinase activity; T cell receptor signaling pathway; protein transport; regulation of small GTPase mediated signal transduction; cellular response to insulin stimulus; small GTPase mediated signal transduction; phospholipid metabolic process; phosphatidylinositol biosynthetic process; positive regulation of transcription factor import into nucleus; insulin receptor signaling pathway; innate immune response; cell glucose homeostasis; regulation of autophagy; positive regulation of transcription from RNA polymerase II promoter; blood coagulation; vascular endothelial growth factor receptor signaling pathway; leukocyte migration

Disease: Megalencephaly-polymicrogyria-polydactyly-hydrocephalus Syndrome 1