Abstract |
The highly conserved molecular chaperones Hsp90 and Hsp70 are indispensible for folding and maturation of a significant fraction of the proteome, including many proteins involved in signal transduction and stress response. To examine the dynamics of chaperone-client interactions after DNA damage, we applied quantitative affinity-purification mass spectrometry (AP-MS) proteomics to characterize interactomes of the yeast Hsp70 isoform Ssa1 and Hsp90 isoform Hsp82 before and after exposure to methyl methanesulfonate. Of 256 proteins identified and quantified via (16)O(/18)O labeling and LC-MS/MS, 142 are novel Hsp70/90 interactors. Nearly all interactions remained unchanged or decreased after DNA damage, but 5 proteins increased interactions with Ssa1 and/or Hsp82, including the ribonucleotide reductase (RNR) subunit Rnr4. Inhibiting Hsp70 or 90 chaperone activity destabilized Rnr4 in yeast and its vertebrate homolog hRMM2 in breast cancer cells. In turn, pre-treatment of cancer cells with chaperone inhibitors sensitized cells to the RNR inhibitor gemcitabine, suggesting a novel chemotherapy strategy. All MS data have been deposited in the ProteomeXchange with identifier PXD001284. BIOLOGICAL SIGNIFICANCE: This study provides the dynamic interactome of the yeast Hsp70 and Hsp90 under DNA damage which suggest key roles for the chaperones in a variety of signaling cascades. Importantly, the cancer drug target ribonucleotide reductase was shown to be a client of Hsp70 and Hsp90 in both yeast and breast cancer cells. As such, this study highlights the potential of a novel cancer therapeutic strategy that exploits the synergy of chaperone and ribonucleotide reductase inhibitors.
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Authors | Andrew W Truman, Kolbrun Kristjansdottir, Donald Wolfgeher, Natalia Ricco, Anoop Mayampurath, Samuel L Volchenboum, Josep Clotet, Stephen J Kron |
Journal | Journal of proteomics
(J Proteomics)
Vol. 112
Pg. 285-300
(Jan 01 2015)
ISSN: 1876-7737 [Electronic] Netherlands |
PMID | 25452130
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Copyright | Copyright © 2014 Elsevier B.V. All rights reserved. |
Chemical References |
- DNA, Fungal
- HSP70 Heat-Shock Proteins
- HSP82 protein, S cerevisiae
- HSP90 Heat-Shock Proteins
- Neoplasm Proteins
- Saccharomyces cerevisiae Proteins
- Ribonucleoside Diphosphate Reductase
- Rnr4 protein, S cerevisiae
- Adenosine Triphosphatases
- SSA1 protein, S cerevisiae
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Topics |
- Adenosine Triphosphatases
(genetics, metabolism)
- Breast Neoplasms
(genetics, metabolism, pathology)
- Cell Line, Tumor
- DNA Damage
- DNA, Fungal
(genetics, metabolism)
- Female
- HSP70 Heat-Shock Proteins
(genetics, metabolism)
- HSP90 Heat-Shock Proteins
(genetics, metabolism)
- Humans
- Neoplasm Proteins
(genetics, metabolism)
- Proteomics
- Ribonucleoside Diphosphate Reductase
(genetics, metabolism)
- Saccharomyces cerevisiae
(genetics, metabolism)
- Saccharomyces cerevisiae Proteins
(genetics, metabolism)
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