Cell · 2004 · 469 citations · 37 references
Life SciencesBiochemistryMolecular BiologyEnzymologyProtein BiochemistryProtein FoldingChaperone-assisted FoldingMolecular ChaperonesProtein AggregationProtein DegradationProtein RefoldingProtein TurnoverChaperone-assisted Protein DegradationChaperone-mediated Protein RefoldingDisaggregationDisaggregation ChaperonesDisaggregation MechanismsHsp70 Chaperone SystemProtein Thermal AdaptationSubstrate Translocation
Cell survival under severe thermal stress requires the ClpB (Hsp104) AAA+ chaperone, which solubilizes and reactivates aggregated proteins together with the DnaK (Hsp70) system. The study aims to determine whether ClpB-mediated disaggregation alone ensures survival or whether reactivation of aggregated proteins is also required, by engineering a BAP variant that converts ClpB into a degrading disaggregase. BAP is a ClpB variant that binds ClpP and translocates substrates through its central pore directly into ClpP for degradation. The study shows that ClpB-dependent substrate translocation into ClpP is essential for disaggregation, that this process still requires DnaK at early stages, and that converting ClpB into a degrading disaggregase fails to confer thermotolerance, indicating that reactivation of aggregated proteins is necessary for survival.
Cell survival under severe thermal stress requires the activity of the ClpB (Hsp104) AAA+ chaperone that solubilizes and reactivates aggregated proteins in concert with the DnaK (Hsp70) chaperone system. How protein disaggregation is achieved and whether survival is solely dependent on ClpB-mediated elimination of aggregates or also on reactivation of aggregated proteins has been unclear. We engineered a ClpB variant, BAP, which associates with the ClpP peptidase and thereby is converted into a degrading disaggregase. BAP translocates substrates through its central pore directly into ClpP for degradation. ClpB-dependent translocation is demonstrated to be an integral part of the disaggregation mechanism. Protein disaggregation by the BAP/ClpP complex remains dependent on DnaK, defining a role for DnaK at early stages of the disaggregation reaction. The activity switch of BAP to a degrading disaggregase does not support thermotolerance development, demonstrating that cell survival during severe thermal stress requires reactivation of aggregated proteins.
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John R. Glover, Susan Lindquist · Cell · 1998 · 1.4K citations · Full text
Protein disaggregation mediated by heat-shock protein Hspl04
Dawn A. Parsell, Anthony S. Kowal, Mike A. Singer et al. · Nature · 1994 · 870 citations
HSP104 Required for Induced Thermotolerance
Yolanda Sánchez, Susan Lindquist · Science · 1990 · 856 citations