RT Journal Article
SR Electronic
T1 Two-step mechanism of J-domain action in driving Hsp70 function
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.01.13.901538
DO 10.1101/2020.01.13.901538
A1 Bartłomiej Tomiczek
A1 Wojciech Delewski
A1 Lukasz Nierzwicki
A1 Milena Stolarska
A1 Igor Grochowina
A1 Brenda Schilke
A1 Rafal Dutkiewicz
A1 Marta A. Uzarska
A1 Szymon J. Ciesielski
A1 Jacek Czub
A1 Elizabeth A. Craig
A1 Jaroslaw Marszalek
YR 2020
UL http://biorxiv.org/content/early/2020/01/13/2020.01.13.901538.abstract
AB J-domain proteins (JDPs), obligatory Hsp70 cochaperones, play critical roles in protein homeostasis. They promote key allosteric transitions that stabilize Hsp70 interaction with substrate polypeptides upon hydrolysis of its bound ATP. Although a recent crystal structure revealed the physical mode of interaction between a J-domain and an Hsp70, the structural and dynamic consequences of J-domain action once bound and how Hsp70s discriminate among its multiple JDP partners remain enigmatic. We combined free energy simulations, biochemical assays and evolutionary analyses to address these issues. Our results indicate that the invariant aspartate of the J-domain perturbs a conserved intramolecular Hsp70 network of contacts that crosses domains. This perturbation leads to destabilization of the domain-domain interface - thereby promoting the allosteric transition that triggers ATP hydrolysis. While this mechanistic step is driven by conserved residues, evolutionarily variable residues are key to initial JDP/Hsp70 recognition - via electrostatic interactions between oppositely charged surfaces. We speculate that these variable residues allow an Hsp70 to discriminate amongst JDP partners, as many of them have coevolved. Together, our data points to a two-step mode of J-domain action, a recognition stage followed by a mechanistic stage.