Protein phosphatase 2A regulatory subunit B55 alpha (B55α (also commonly abbreviated as PPP2R2A))

Protein phosphatase 2A regulatory subunit B55 alpha, encoded by the PPP2R2A gene, is a regulatory subunit of the heterotrimeric serine/threonine phosphatase PP2A. The B55 alpha subunit determines substrate specificity and cellular localization of the PP2A complex. It plays a key role in the regulation of the cell cycle, especially in entry into and exit from mitosis, by controlling the phosphorylation status of central cell cycle regulators and kinases. B55 alpha also participates in a wide array of cellular processes, including apoptosis, differentiation, DNA damage repair, mitochondrial function, and cytoskeleton organization. Dysfunction or mutations in the regulatory subunits—including B55 alpha—have been implicated in the pathogenesis of cancers and various neurodegenerative and neurodevelopmental disorders.

Other names

B55 alphaPPP2R2APR55 alphaPP2A-B55αSerine/threonine-protein phosphatase 2A 55 kDa regulatory subunit A

Modulation of phosphorylation status of multiple signaling proteins by dephosphorylating serine/threonine residues, thus acting as a negative regulator of kinase-driven pathways such as the AKT and MAPK cascades.