5hpe
Phosphatase domain of PP5 bound to a phosphomimetic Cdc37 substrate peptide
Structural highlights
FunctionCDC37_HUMAN Co-chaperone that binds to numerous kinases and promotes their interaction with the Hsp90 complex, resulting in stabilization and promotion of their activity.[1] PPP5_HUMAN May play a role in the regulation of RNA biogenesis and/or mitosis. In vitro, dephosphorylates serine residues of skeletal muscle phosphorylase and histone H1. Publication Abstract from PubMedThe serine/threonine phosphatase protein phosphatase 5 (PP5) regulates hormone- and stress-induced cellular signaling by association with the molecular chaperone heat shock protein 90 (Hsp90). PP5-mediated dephosphorylation of the cochaperone Cdc37 is essential for activation of Hsp90-dependent kinases. However, the details of this mechanism remain unknown. We determined the crystal structure of a Cdc37 phosphomimetic peptide bound to the catalytic domain of PP5. The structure reveals PP5 utilization of conserved elements of phosphoprotein phosphatase (PPP) structure to bind substrate and provides a template for many PPP-substrate interactions. Our data show that, despite a highly conserved structure, elements of substrate specificity are determined within the phosphatase catalytic domain itself. Structure-based mutations in vivo reveal that PP5-mediated dephosphorylation is required for kinase and steroid hormone receptor release from the chaperone complex. Finally, our data show that hyper- or hypoactivity of PP5 mutants increases Hsp90 binding to its inhibitor, suggesting a mechanism to enhance the efficacy of Hsp90 inhibitors by regulation of PP5 activity in tumors. Structural and functional basis of protein phosphatase 5 substrate specificity.,Oberoi J, Dunn DM, Woodford MR, Mariotti L, Schulman J, Bourboulia D, Mollapour M, Vaughan CK Proc Natl Acad Sci U S A. 2016 Jul 27. pii: 201603059. PMID:27466404[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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