Metal-dependent protein phosphatases (PPM) include protein phosphatases which dependent on manganese/magnesium ions (Mn²⁺/Mg²⁺). PPM group contains a high conserved catalytic domain instead of catalytic subunit and different regulatory domains determining the substrate recognition and function diversity. Like PPP group, metal ions play an important role in dephosphorylation reaction (1). PP2C contains 19 members in human genome, including PP2C like phosphatases. What's more, PP2C is one of the largest type of protein phosphatases in plants with at least 76 members in Arabidopsis thaliana. PP2C family members are involved in varieties of cellular processes including cell cycle, splicing, cellular stress signaling and some members function as tumor suppressor (2).

Reference
1. Shi, Y. (2009) Serine/threonine phosphatases: mechanism through structure. Cell, 139, 468-484. PMID: 19879837
2. Lammers, T. and Lavi, S. (2007) Role of type 2C protein phosphatases in growth regulation and in cellular stress signaling. Crit Rev Biochem Mol Biol, 42, 437-461. PMID: 18066953