Protein phosphatase 2A (PP2A) forms several holoenzyme complexes. The core enzyme consists of a catalytic C subunit (PP2Ac) and a regulatory A subunit (PR65) that is associated with a regulatory B subunit. The regulatory B subunit can be classified as a member of the B, B' or B'' families [].PPP2R3C is a B'' family member and a regulatory B subunit of PP2A. It is also a subunit of the PP5/PPP2R3C complex. Both PP2A and PP5 are serine/threonine specific phosphatases. The PP5/PPP2R3C complex dephosphorylates P-glycoprotein/ABCB1 and down-regulates its expression and function []. This entry also includes TONNEAU2/FASS from Arabidopsis. TONNEAU2 is the B'' subunit of protein phosphatase 2A that regulates interphase microtubule nucleation [].
