Type 2C protein phosphatases in plants

Type 2C protein phosphatases (PP2Cs) form a structurally unique class of Mg 2+ ‐/Mn 2+ ‐dependent enzymes. PP2Cs are evolutionary conserved from prokaryotes to higher eukaryotes and play a prominent role in stress signalling. In this review, we focus on the evolution, function and regulation of the plant PP2Cs. Members of a subclass of plant PP2Cs counteract mitogen‐activated protein kinase pathways, whereas members of other subfamilies function as co‐receptors for the phytohormone abscisic acid. Recent structural analyses of abscisic acid receptors have elucidated the mode of ligand‐dependent regulation and substrate targeting.