Phosphorylation and Ubiquitination Regulate Protein Phosphatase 5 Activity and Its Prosurvival Role in Kidney Cancer.

Published

Journal Article

The serine/threonine protein phosphatase 5 (PP5) regulates multiple cellular signaling networks. A number of cellular factors, including heat shock protein 90 (Hsp90), promote the activation of PP5. However, it is unclear whether post-translational modifications also influence PP5 phosphatase activity. Here, we show an "on/off switch" mechanism for PP5 regulation. The casein kinase 1δ (CK1δ) phosphorylates T362 in the catalytic domain of PP5, which activates and enhances phosphatase activity independent of Hsp90. Overexpression of the phosphomimetic T362E-PP5 mutant hyper-dephosphorylates substrates such as the co-chaperone Cdc37 and glucocorticoid receptor in cells. Our proteomic approach revealed that the tumor suppressor von Hippel-Lindau protein (VHL) interacts with and ubiquitinates K185/K199-PP5 for proteasomal degradation in a hypoxia- and prolyl-hydroxylation-independent manner. Finally, VHL-deficient clear cell renal cell carcinoma (ccRCC) cell lines and patient tumors exhibit elevated PP5 levels. Downregulation of PP5 causes ccRCC cells to undergo apoptosis, suggesting a prosurvival role for PP5 in kidney cancer.

Full Text

Duke Authors

Cited Authors

  • Dushukyan, N; Dunn, DM; Sager, RA; Woodford, MR; Loiselle, DR; Daneshvar, M; Baker-Williams, AJ; Chisholm, JD; Truman, AW; Vaughan, CK; Haystead, TA; Bratslavsky, G; Bourboulia, D; Mollapour, M

Published Date

  • November 14, 2017

Published In

Volume / Issue

  • 21 / 7

Start / End Page

  • 1883 - 1895

PubMed ID

  • 29141220

Pubmed Central ID

  • 29141220

Electronic International Standard Serial Number (EISSN)

  • 2211-1247

Digital Object Identifier (DOI)

  • 10.1016/j.celrep.2017.10.074

Language

  • eng

Conference Location

  • United States