Diversity in the regulatory B-subunits of protein phosphatase 2A: identification of a novel isoform highly expressed in brain

A fast purification procedure helps purify two trimeric forms of protein phosphatase 2A containing distinct B-subunits, PP2A(0) and PP2A(1), from rabbit skeletal muscle. Gel electrophoresis reveals the different mobility of these B-subunits and indicates different immunological properties. Cloning of cDNAs with the B subunit of PP2A results in the isolation of a novel isoform B-gamma. Sequential analysis of the isoform shows that B-gamma encodes a protein exhibiting 81% and 87% similarity with that of the B-alpha and the B-beta form, respectively. Northern blot analysis reveals the high expression of B-gamma isoform in rabbit brain.