Thermotolerance requires refolding of aggregated proteins by substrate translocation through the central pore of ClpB.
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.
Weibezahn
Jimena
J
Zentrum für Molekulare Biologie der Universität Heidelberg, Universität Heidelberg, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany.
Tessarz
Peter
P
Schlieker
Christian
C
Zahn
Regina
R
Maglica
Zeljka
Z
Lee
Sukyeong
S
Zentgraf
Hanswalter
H
Weber-Ban
Eilika U
EU
Dougan
David A
DA
Tsai
Francis T F
FT
Mogk
Axel
A
Bukau
Bernd
B
D002470:Cell Survival / Q000235:genetics; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018869:Heat-Shock Response / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D020409:Molecular Motor Proteins; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D015202:Protein Engineering; D017510:Protein Folding; D021381:Protein Transport / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D020409:Molecular Motor Proteins; D046912:Multiprotein Complexes; D049071:Endopeptidase Clp; C063842:dnaK protein, E coli; C069775:ClpB protein, E coli