PIK3R1

Phosphatidylinositol 3-kinase regulatory subunit alpha (encoded by PIK3R1, alias p85α) is the core regulatory subunit of class I PI3K. It forms complexes with catalytic subunits (e.g., p110α) to modulate PI3K activity, mediating conversion of PIP2 to PIP3 and activating the PI3K-AKT pathway—key for cell proliferation, survival, and glucose metabolism.
PIK3R1 mutations or dysregulation drive cancers (breast, colorectal) via aberrant PI3K-AKT signaling and link to metabolic disorders like type 2 diabetes. PI3K inhibitors (e.g., alpelisib) targeting the complex are clinically used; specific PIK3R1-targeted therapies remain in preclinical development to address pathway dysfunctions.