Phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3)

Phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) encodes the p55 gamma regulatory subunit of the class IA phosphoinositide 3-kinase (PI3K) enzyme complex[2][5]. It binds to the p110 catalytic subunit and activated protein tyrosine kinases via its SH2 domains, regulating PI3K lipid kinase activity that is essential for producing PIP3 at the plasma membrane in response to extracellular signals. PIK3R3 is involved in signaling pathways that control cell growth, proliferation, survival, and metabolism. It is upregulated in several cancers and promotes tumor cell proliferation, potentially through mechanisms partly independent of classical Akt pathway activation[4][6]. PIK3R3 may be a novel therapeutic target, particularly in cancers exhibiting dysregulated PI3K pathway signaling. However, no selective drugs currently target PIK3R3 as a single agent.

Other names

p55 gammaphosphatidylinositol 3-kinase regulatory subunit gammaPI3-kinase regulatory subunit gammaPI3K regulatory subunit gammaPI3-kinase subunit p55-gammaPtdIns-3-kinase regulatory subunit p55-gammaphosphoinositide-3-kinase regulatory subunit gammap55PIKp55-GAMMA

PI3K inhibitors prevent production of phosphatidylinositol-3,4,5-trisphosphate (PIP3), blocking downstream signaling important for cell survival and proliferation[3][4]. Knockdown or inhibition induces G0/G1 cell cycle arrest and reduces cell proliferation[4][6].