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. Pyruvate dehydrogenase phosphatase (PDP) also contain conserved PP2C catalytic domain. PDP mainly mediates the dephosphorylation of Pyruvate dehydrogenase (E1), one of the three components (E1, E2, and E3) of the large pyruvate dehydrogenase complex. Two isoforms of PDPc have been identified, PDP1 and PDP2. Both of them are magnesium dependent, although PDP2 requires a 10-fold higher Mg²⁺ concentration for its activity. PDP1 requires calcium and the interaction with E2. PDP1 is highly expressed in skeletal muscle and PDP2 reaches a high level in liver and adipocytes. Defects of PDP are involved in disease, such as lactic acidemia (1).

Reference
1. Maj, M.C., MacKay, N., Levandovskiy, V., Addis, J., Baumgartner, E.R., Baumgartner, M.R., Robinson, B.H. and Cameron, J.M. (2005) Pyruvate dehydrogenase phosphatase deficiency: identification of the first mutation in two brothers and restoration of activity by protein complementation. J Clin Endocrinol Metab, 90, 4101-4107. PMID: 18066953

    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