Proteasome-Bound UCH37/UCHL5 Debranches Ubiquitin Chains to Promote Degradation.

ABSTRACT: The linkage, length, and architecture of ubiquitin (Ub) chains are all important variables in providing tight control over many biological paradigms. There are clear roles for branched architectures in regulating proteasome-mediated degradation, but the proteins that selectively recognize and process these atypical chains are unknown. Here, using synthetic and enzyme-derived ubiquitin chains along with intact mass spectrometry, we report that UCH37/UCHL5, a proteasome-associated deubiquitinase, cleaves K48 branched chains. The activity and selectivity toward branched chains is markedly enhanced by the proteasomal Ub receptor RPN13/ADRM1. Using reconstituted proteasome complexes, we find that chain debranching promotes degradation of substrates modified with branched chains under multi-turn

SUBMITTER: Deol KK 

PROVIDER: S-EPMC7718437 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature