PP2Cγ: a human protein phosphatase with a unique acidic domain1

Abstract
We have cloned a novel cDNA from human skeletal muscle which encodes a protein phosphatase with a unique acidic domain. It is 34% identical to mammalian PP2Cα and PP2Cβ, and we call it PP2Cγ. It more closely resembles PP2Cs from Paramecium tetraurelia and Schizosaccharomyces pombe than mammalian PP2Cs. Northern blot analysis shows that PP2Cγ is widely expressed, and is most abundant in testis, skeletal muscle, and heart. Like known PP2Cs, recombinant PP2Cγ requires Mg2+ or Mn2+ for activity. Unlike any other known phosphatase, PP2Cγ has a highly acidic domain: 75% of the 54 residues are glutamate or aspartate.