※ PDP family introduction

    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