PP2A is a major serine/threonine phosphatase that is implicated in the negative control of cell cycle progression. It is a trimeric holoenzyme that is comprised of a catalytic, structural, and regulatory subunit. PPP2R5D is a regulatory subunit of PP2A. The regulatory subunits of PP2A are grouped into 3 families: B/PR55, B’/PR61, and B’’/PR72. PPP2R5D encodes the delta isoform of the B’ subunit, B56. PPP2R5D may function to localize PP2A to the nucleus. serine/threonine-protein phosphatase 2A 56 kDa regulatory subunit delta isoform, PP2A B subunit B’ delta isoform, PP2A B subunit B56 delta isoform, PP2A B subunit PR61 delta isoform, PP2A B subunit R5 delta isoform, B56D, MGC2134, MGC8949.