Characterization of Hsp70 Binding and Nucleotide Exchange by the Yeast Hsp110 Chaperone Sse1
- 18 November 2006
- journal article
- research article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 45 (50) , 15075-15084
- https://doi.org/10.1021/bi061279k
Abstract
SSE1 and SSE2 encode the essential yeast members of the Hsp70-related Hsp110 molecular chaperone family. Both mammalian Hsp110 and the Sse proteins functionally interact with cognate cytosolic Hsp70s as nucleotide exchange factors. We demonstrate here that Sse1 forms high-affinity (Kd ∼ 10-8 M) heterodimeric complexes with both yeast Ssa and mammalian Hsp70 chaperones and that binding of ATP to Sse1 is required for binding to Hsp70s. Sse1·Hsp70 heterodimerization confers resistance to exogenously added protease, indicative of conformational changes in Sse1 resulting in a more compact structure. The nucleotide binding domains of both Sse1/2 and the Hsp70s dictate interaction specificity and are sufficient for mediating heterodimerization with no discernible contribution from the peptide binding domains. In support of a strongly conserved functional interaction between Hsp110 and Hsp70, Sse1 is shown to associate with and promote nucleotide exchange on human Hsp70. Nucleotide exchange activity by Sse1 is physiologically significant, as deletion of both SSE1 and the Ssa ATPase stimulatory protein YDJ1 is synthetically lethal. The Hsp110 family must therefore be considered an essential component of Hsp70 chaperone biology in the eukaryotic cell.Keywords
This publication has 36 references indexed in Scilit:
- Chaperone network in the yeast cytosol: Hsp110 is revealed as an Hsp70 nucleotide exchange factorThe EMBO Journal, 2006
- Molecular chaperones of the Hsp110 family act as nucleotide exchange factors of Hsp70sThe EMBO Journal, 2006
- Global analysis of protein expression in yeastNature, 2003
- HspBP1, a homologue of the yeast Fes1 and Sls1 proteins, is an Hsc70 nucleotide exchange factorFEBS Letters, 2002
- Overexpression of Yeast Hsp110 Homolog Sse1p Suppressesydj1-151Thermosensitivity and Restores Hsp90-dependent ActivityMolecular Biology of the Cell, 2002
- Nucleotide Exchange Factor for the Yeast Hsp70 Molecular Chaperone Ssa1pMolecular and Cellular Biology, 2002
- The in vivo function of the ribosome-associated Hsp70, Ssz1, does not require its putative peptide-binding domainProceedings of the National Academy of Sciences, 2002
- Molecular Chaperones in the Cytosol: from Nascent Chain to Folded ProteinScience, 2002
- Modulation of the Chaperone Activities of Hsc70/Hsp40 by Hsp105α and Hsp105βBiochemical and Biophysical Research Communications, 2000
- The Hsp110 and Grp170 stress proteins: newly recognized relatives of the Hsp70sCell Stress and Chaperones, 2000