Protein phosphatase 2A-α (PP2A-α) is also known as protein phosphatase 2A activator. PP2A is one of the four major serine/threonine phosphatases and is a human tumor suppressor that inhibits cellular transformation. PP2A α gene encodes a specific phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase-2A. Protein phosphatase 2A holoenzyme is a heterotrimeric protein composed of a structural subunit A, a catalytic subunit C, and a regulatory subunit B. PTP2A α can alter the substrate specificity of PP2A leading to enhanced phosphotyrosine phosphatase activity and decreased phosphoserine phosphatase activity. The gene encoding this protein is localized on human chromosome 5q31.1.
