Protein phosphatase 1

Abstract

Protein phosphatase 1 (PP1) is one of the first protein phosphatases whose activity was detected and whose catalytic subunit (PP1c) was purified and cloned. It is the representative of the most ancient protein phosphatase family that has a ubiquitous distribution in all eukaryotic organisms. The high level of conservation of the amino acid sequence and protein architecture of the PP1c is remarkable, and the identification of its very similar isoforms was an unexpected result of molecular cloning. The enzyme has a large number of interacting proteins, which tether PP1c to well defined locations and/or regulate its activity. A dynamic exchange of these non-catalytic subunits and the broad substrate specificity of the phosphatase are consistent with a wide range of physiological roles including cell cycle regulation, centrosome separation, interphase chromosome condensation, glycogen metabolism, contractility, morphogenesis, spermatogenesis, learning and memory, as inferred from genetic studies and predicted from biochemical experiments.