Protein Phosphatase 2 A/B delta

PP2A is a heterotrimeric phosphatase, ccomposed of A, B and C subunits. The structural A and catalytic C subunits form the constitutive core of the enzyme, which associates with one of a large number of regulatory B subunits. Three families of B subunits have been identified thus far. The prototypical B (or PR55) family of subunits is encoded by three genes, B?, B? and B?. The B' (or B56) family consists of at least seven splice variants derived from five genes. RNA's for the two members of the B'' family, PR72 and PR130, arise by alternative splicing or use of alternate transcription start sites from the same gene. Primary structures as well as functions of B and B' subunits are conserved from yeast to mammals. B? is a novel isoform of the B class of PP2A regulatory subunits. It is widely expressed in rat tissues and appears to be involved in targeting PP2A to the cytosolic compartment.