Phosphatase 2A affects a variety of biological processes in the cell such as transcription, cell cycle progression and cellular morphogenesis, and provides an initial identification of critical substrates for this phosphatase. The regulatory subunit may direct the catalytic subunit to distinct, albeit overlapping, subsets of substrates. PP2A exists in several trimeric forms, all of which consist of a core composed of a catalytic subunit associated with a 65 kDa regulatory subunit (PR65) (subunit A). The core complex associates with a third, variable subunit (subunit B), which confers distinct properties to the holoenzyme. Each HEAT repeat appears to consist of two alpha helices joined by a hydrophilic region, the intrarepeat loop. The repeat units may be arranged laterally to form a rod-like structure. Present with 16900 molecules/cell in log phase SD medium. Belongs to the phosphatase 2A regulatory subunit A family.