Protein phosphatase 1 (PP1) is a major eukaryotic serine/threonine phosphatase that is involved in a multitude of cellular functions. PP1 is a holoenzyme that consists of the PP1 catalytic subunit (PP1c) that associates with and is regulated by over 50 regulatory subunits. There are several gene and alternative splice products of the catalytic subunit PP1c. PPP1CA encodes the PP1 alpha catalytic subunit. In addition to PP1 alpha, there is PP1 beta (PPP1CB), and two splice variants of PP1 gamma (PPP1CC). The mutually exclusive interaction between the various catalytic and regulatory subunits allows the PP1 enzyme to be involved in a variety of functions which include cell division, glycogen metabolism, muscle contractility, and protein synthesis. serine/threonine-protein phosphatase PP1-alpha catalytic subunit, PPP1A, PP-1A, MGC1674, MGC15877.