Serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A alpha isoform is a protein in humans that is encoded by PPP2R1A gene. The PR65 subunit of protein phosphatase 2A serves as a scaffolding molecule to coordinate the assembly of the catalytic subunit and a variable regulatory B subunit. Upon interaction with GNA12 promotes dephosphorylation of microtubule associated protein TAU/MAPT.