Protein Phosphatase 2, Regulatory Subunit B Alpha (PPP2R2a)

Protein phosphorylation on serine and threonine residues by protein kinases is responsible for the communication of many intracellular signals. Equally important is the dephosphorylation of proteins by serine/threonine phosphatases. Protein phosphatase-2A (PP2A), a heterotrimeric serine/threonine phosphatase, has a particularly complex set of regulatory subunits controlling its function and localization. The deduced 447-amino acid PPP2R2A protein has a calculated molecular mass of approximately 52 kD. SDS-PAGE analysis, however, showed that PPP2R2A was expressed as a 55-kD protein. The nucleotide sequence of PPP2R2A is 75% identical to PPP2R2B in the coding region. Northern blot analysis detected PPP2R2A transcripts of 2.3 and 2.5 kb, as well as a less abundant one of 4.4 kb, in all cell lines examined.