PPP family of serine/threonine protein phosphatases: Key players in plant development and adaptive responses

Abstract

Reversible protein phosphorylation is a major form of post-translational modification that regulates many cellular processes. Although there are few plant protein phosphatases in comparison with their protein kinase partners, their function is as relevant as that of protein kinases. Many serine/threonine (ser/thr) protein phosphatases have been identified in plants: PP1, PP2A, PP2C, PP4, PP5, PP6, PP7, protein phosphatases with kelch-repeat domains and bacterial-like protein phosphatases. Over the last three decades of research, the cellular functions of plant ser/thr phosphatases have been documented, and specific roles for these enzymes have been characterized with increasing detail. The functional characterization has been accompanied by structural and biochemical data, leading to major advances in the understanding of their molecular mechanism of action. This chapter is focused on the structure, regulation and functions of PPP ser/thr phosphatases in higher plants.