Ubiquitin modulates 26S proteasome conformational dynamics and promotes substrate degradation.

ABSTRACT: The 26S proteasome recognizes thousands of appropriate protein substrates in eukaryotic cells through attached ubiquitin chains and uses its adenosine triphosphatase (ATPase) motor for mechanical unfolding and translocation into a proteolytic chamber. Here, we used single-molecule Förster resonance energy transfer measurements to monitor the conformational dynamics of the proteasome, observe individual substrates during their progression toward degradation, and elucidate how these processes are regulated by ubiquitin chains. Rapid transitions between engagement- and processing-competent proteasome conformations control substrate access to the ATPase motor. Ubiquitin chain binding functions as an allosteric regulator to slow these transitions, stabilize the engagement-competent state

SUBMITTER: Jonsson E 

PROVIDER: S-EPMC9788759 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature