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Sci Rep. 2015 Nov 23;5:17058. doi: 10.1038/srep17058.

The activity of protein phosphatase 5 towards native clients is modulated by the middle- and C-terminal domains of Hsp90.

Author information

1
Center for Integrated Protein Science Munich at the Department Chemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany.
2
Medical Proteome Center, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
3
Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
4
Institute of Molecular Biology &Biochemistry, Center of Molecular Medicine, Medical University of Graz, 8010 Graz, Austria.
5
Omics Center Graz, BioTechMed Graz, 8010 Graz, Austria.

Abstract

Protein phosphatase 5 is involved in the regulation of kinases and transcription factors. The dephosphorylation activity is modulated by the molecular chaperone Hsp90, which binds to the TPR-domain of protein phosphatase 5. This interaction is dependent on the C-terminal MEEVD motif of Hsp90. We show that C-terminal Hsp90 fragments differ in their regulation of the phosphatase activity hinting to a more complex interaction. Also hydrodynamic parameters from analytical ultracentrifugation and small-angle X-ray scattering data suggest a compact structure for the Hsp90-protein phosphatase 5 complexes. Using crosslinking experiments coupled with mass spectrometric analysis and structural modelling we identify sites, which link the middle/C-terminal domain interface of C. elegans Hsp90 to the phosphatase domain of the corresponding kinase. Studying the relevance of the domains of Hsp90 for turnover of native substrates we find that ternary complexes with the glucocorticoid receptor (GR) are cooperatively formed by full-length Hsp90 and PPH-5. Our data suggest that the direct stimulation of the phosphatase activity by C-terminal Hsp90 fragments leads to increased dephosphorylation rates. These are further modulated by the binding of clients to the N-terminal and middle domain of Hsp90 and their presentation to the phosphatase within the phosphatase-Hsp90 complex.

PMID:
26593036
PMCID:
PMC4655416
DOI:
10.1038/srep17058
[Indexed for MEDLINE]
Free PMC Article

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