Protein phosphatase 2A (PP2A) is the most abundant phosphatase specific for serine and threonine phosphorylation in mammalian cells. Dephosphorylation of substrates targeted by PP2A plays a vital role in a large variety of cellular processes including signal transduction, regulation of the cell cycle, gene expression and development. Protein phosphatase 2 is one of the four major Ser/Thr phosphatases, and it is implicated in the negative control of cell growth and division. It consists of a common heteromeric core enzyme, which is composed of a catalytic subunit and a constant regulatory subunit, that associates with a variety of regulatory subunits. The constant regulatory subunit alpha serves as a scaffolding molecule to coordinate the assembly of the catalytic subunit and a variable regulatory beta subunit.Synonyms: PP2A-alpha, Protein Phospatase 2A, Replication protein C, Serine/threonine-protein phosphatase 2A catalytic subunit alpha isoform