InterPro domain: IPR041753

Serine/threonine protein phosphatase-5 (PP5) is a member of the PPP gene family of protein phosphatases that is highly conserved among eukaryotes and widely expressed in mammalian tissues. PP5 has a C-terminal phosphatase domain and an extended N-terminal TPR (tetratricopeptide repeat) domain containing three TPR motifs [ 1 , 2 , 3 , 4 , 5 ]. This entry represents the C-terminal phosphatase domain. Proteins containing this domain also include yeast Ppt1, which is a serine/threonine phosphatase that regulates Hsp90 chaperone by affecting its ATPase and cochaperone binding activitie [ 6 ].

The PPP (phosphoprotein phosphatase) family is one of two known protein phosphatase families specific for serine and threonine. The PPP family also includes: PP1, PP2A, PP2B (calcineurin), PP4, PP6, PP7, Bsu1, RdgC, PrpE, PrpA/PrpB, and ApA4 hydrolase. The PPP catalytic domain is defined by three conserved motifs (-GDXHG-, -GDXVDRG- and -GNHE-). The PPP enzyme family is ancient with members found in all eukaryotes, and in most bacterial and archeal genomes. Dephosphorylation of phosphoserines and phosphothreonines on target proteins plays a central role in the regulation of many cellular processes [ 7 , 8 ]. PPPs belong to the metallophosphatase (MPP) superfamily.

1. Protein phosphatase 5. Trends Endocrinol. Metab. 40, 2358-62
2. Protein phosphatase 5 in signal transduction. Cell. Signal. 12, 28-32
3. RdgC/PP5-related phosphatases: novel components in signal transduction. Mol. Cell. Biol. 11, 555-62
4. Protein phosphatase 5 is required for ATR-mediated checkpoint activation. Mol. Cell 25, 9910-9
5. Structural basis for the catalytic activity of human serine/threonine protein phosphatase-5. J. Biol. Chem. 279, 33992-9
6. Hsp90-dependent activation of protein kinases is regulated by chaperone-targeted dephosphorylation of Cdc37. null 31, 886-95
7. The structure and mechanism of protein phosphatases: insights into catalysis and regulation. Biochem. Cell Biol. 27, 133-64
8. Protein phosphatases: structures and implications. Int. J. Biochem. Cell Biol. 75, 17-26