Protein phosphatase 2A (PP2A) is a major intracellular proteinphosphatase that regulates multiple aspects of cell growth and metabolism.The ability of this widely distributed heterotrimeric enzyme to act on adiverse array of substrates is largely controlled by the nature of itsregulatory B subunit. There are multiple families of B subunits, this family is called the B56 family [<cite idref="PUB00002927"/>].