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Cell Rep. 2017 Nov 14;21(7):1883-1895. doi: 10.1016/j.celrep.2017.10.074.

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

Author information

1
Department of Urology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA.
2
Department of Urology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA.
3
Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
4
Department of Chemistry, Syracuse University, 1-014 Center for Science and Technology, Syracuse, NY 13244, USA.
5
Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
6
Institute of Structural and Molecular Biology, University College London and Birkbeck College, Biological Sciences, Malet Street, London WC1E 7HX, UK.
7
Department of Urology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA. Electronic address: mollapom@upstate.edu.

Abstract

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.

KEYWORDS:

PP5; VHL; casein kinase-1 δ; clear cell renal cell carcinoma; co-chaperone; heat shock protein 90; kidney cancer; molecular chaperone; serine/threonine phosphatase 5; von Hippel-Lindau protein

PMID:
29141220
PMCID:
PMC5699234
DOI:
10.1016/j.celrep.2017.10.074
[Indexed for MEDLINE]
Free PMC Article

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