The molecular chaperone Hsp90 plays a role in the assembly and maintenance of the 26S proteasome

Imai, Jun

doi:10.1093/emboj/cdg349

Cited by 216 publications

(151 citation statements)

References 25 publications

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“…Among the stable PIPs, there are three types of chaperone proteins including heat shock protein and components of the AP-3 and CCT complexes. Consistent with these findings, various heat shock proteins have been shown to interact with yeast proteasomes (7,15) and were suggested to facilitate delivery of aggregation-prone substrates for degradation (30,32) or to play a role in the proteasome structural integrity and assembly (31). In contrast, the interactions of the AP-3 and CCT complexes with the human proteasomes have not been reported before.…”

Section: -H Map-silacmentioning

confidence: 57%

Identifying Dynamic Interactors of Protein Complexes by Quantitative Mass Spectrometry

Wang

Huang

2008

Molecular & Cellular Proteomics

184

221

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Dynamically interacting proteins associate and dissociate with their binding partners at high on/off rates. Although their identification is of great significance to proteomics research, lack of an efficient strategy to distinguish stable and dynamic interactors has hampered the efforts toward this goal. In this work, we developed a new method, MAP (mixing after purification)-SILAC (stable isotope labeling of amino acids in cell culture), to quantitatively investigate the interactions of protein complexes by mass spectrometry. In combination with the original SILAC approach, stable and dynamic components were effectively distinguished by the differences in their relative abundance ratio changes. We applied the newly developed strategies to decipher the dynamics of the human 26 S proteasomeinteracting proteins. A total of 67 putative human proteasome-interacting proteins were identified by the MAP-SILAC method among which 14 proteins would have been misidentified as background proteins due to low relative abundance ratios in standard SILAC experiments and 57 proteins have not been reported previously. In addition, 35 of the 67 proteins were classified as stable interactors of the proteasome complex, whereas 16 of them were identified as dynamic interactors. The methods reported here provide a valuable expansion of proteomics technologies for identification of important but previously unidentifiable interacting proteins. Molecular & Cellular Proteomics 7:46 -57, 2008.Protein-protein interactions are one of the major mechanisms for controlling protein functions in various cellular processes. To fully understand these functions, global mapping of protein-protein interactions has become a major goal in current proteomics research. MS in combination with affinity purification in particular has evolved as a powerful tool for deciphering protein interaction networks at the proteome level (1-6). Although conventional affinity purification can preserve stable interactions under native conditions, we have shown recently that affinity purification coupled with in vivo crosslinking can extend identification of interacting proteins by capturing weak affinity or transient interactors (7). In contrast to stably interacting proteins, dynamically interacting proteins associate and dissociate with their binding partners at high on/off rates and are likely to be more susceptible to rapid regulation in response to cellular cues. Their identification is of great significance to proteomics research but is considerably challenging as efficient strategies to distinguish between stable and dynamic components of protein complexes are currently lacking. A new development that adds the ability to describe protein complex dynamics is thus needed for the advancement of interactive proteomics.Identification of specific protein interactions has been successfully achieved by quantitative MS using stable isotope labeling such as the stable isotope labeling of amino acids in cell culture (SILAC) 1 strategy, which allows effective discrimination ag...

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Section: -H Map-silacmentioning

confidence: 57%

Identifying Dynamic Interactors of Protein Complexes by Quantitative Mass Spectrometry

Wang

Huang

2008

Molecular & Cellular Proteomics

184

221

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“…Studies, primarily with animals, have revealed that Hsp90 plays roles in a diverse array of cellular processes including protein folding, stress responses, signal transduction, and genomic silencing. Recent studies show that Hsp90 also plays a critical role in the ATP-dependent assembly of the 26 S proteasome (17). Other studies suggest that Hsp90 acts as a buffer against genetic variation as a capacitor of phenotypic variation in plants as in fruit flies (18,19).…”

mentioning

confidence: 99%

Molecular Chaperone Hsp90 Associates with Resistance Protein N and Its Signaling Proteins SGT1 and Rar1 to Modulate an Innate Immune Response in Plants

Liu¹,

Burch‐Smith²,

Schiff

et al. 2004

Journal of Biological Chemistry

314

268

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SGT1 and Rar1 are important signaling components of resistance (R) gene-mediated plant innate immune responses. Here we report that SGT1 and Rar1 associate with the molecular chaperone Hsp90. In addition, we show that Hsp90 associates with the resistance protein N that confers resistance to tobacco mosaic virus. This suggests that Hsp90-SGT1-Rar1 and R proteins might exist in one complex. Suppression of Hsp90 in Nicotiana benthamiana plants shows that it plays an important role in plant growth and development. In addition, Hsp90 suppression in NN plants compromises N-mediated resistance to tobacco mosaic virus. Our results reveal a new role for SGT1-and Rar1-associated chaperone machinery in R gene-mediated defense signaling.

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“…56 These findings may provide new mechanistic insight into the cooperative interactions between the molecular chaperone and proteolysis systems. In the same study, we found that in vivo and in vitro inactivation of Hsp90 caused dissociation of the 26S proteasomes into their constituents.…”

Section: Molecular Chaperonesmentioning

confidence: 93%

“…63 Moreover, molecular chaperones, such as Hsp70 and Hsp90, are responsible for the maintenance of functional states of the UPS pathway, particularly the 26S proteasome as mentioned above. 56 These observations uncover a strong functional link between UPS and molecular chaperones.…”

Section: Perspectivesmentioning

confidence: 95%

Proteasomes and Molecular Chaperones : Cellular Machinery Responsible for Folding and Destruction of Unfolded Proteins

Imai¹,

Yashiroda²,

Maruya³

et al. 2003

Cell Cycle

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Molecular chaperones recognize proteins of non-native structure, prevent them from irreversible intracellular aggregation, and then act with regulatory co-chaperones in the conversion of proteins to be properly folded and in a functional state. However, not every non-native protein is folded successfully. Those proteins that are not accurately folded/ refolded are then directed to the ubiquitin-proteasome system (UPS) for destruction. Both chaperones and proteasomes act jointly together for selective removal of proteins with aberrant structure so as to keep protein homeostasis in cells. Though the precise nature of the cooperative linkage between chaperone and UPS pathways remains largely elusive so far, accumulating evidence from in vivo and in vitro studies shed some light on the molecular mechanisms that link proteasomes and molecular chaperones. This review focuses on how unfolded proteins are handled by these two machineries.

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The molecular chaperone Hsp90 plays a role in the assembly and maintenance of the 26S proteasome

Cited by 216 publications

References 25 publications

Identifying Dynamic Interactors of Protein Complexes by Quantitative Mass Spectrometry

Identifying Dynamic Interactors of Protein Complexes by Quantitative Mass Spectrometry

Molecular Chaperone Hsp90 Associates with Resistance Protein N and Its Signaling Proteins SGT1 and Rar1 to Modulate an Innate Immune Response in Plants

Proteasomes and Molecular Chaperones : Cellular Machinery Responsible for Folding and Destruction of Unfolded Proteins

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