CELLULAR FUNCTION OF PROTEIN PHOSPHATASE 2C IN YEAST

Protein phosphatase 2C (PP2C) is one of four major classes of protein serine/threonine-phosphatases, which requires Mg2+ for its activity. P P2C activity distributes ubiquitously among eukaryotes and enzymes pur ified from mammalian tissues were well characterized biochemically, ho wever, very little is known about their biological function. We have b een trying to identify cellular function of PP2C by genetic analyses i n fission yeast Schizosaccharomyces pombe. So far, three PP2C homologs , ptc1(+), ptc2(+), and ptc3(+), have been cloned and their activity w ere detected in the S. pombe cell lysates. Experiments using ptc mutan ts constructed by gene disruption technique have revealed the involvem ent of PP2C in the heat shock response and possibly osmoregulation in yeast cells.