A Linear Diubiquitin-Based Probe for Efficient and Selective Detection of the Deubiquitinating Enzyme OTULIN.

ABSTRACT: The methionine 1 (M1)-specific deubiquitinase (DUB) OTULIN acts as a negative regulator of nuclear factor ?B signaling and immune homeostasis. By replacing Gly76 in distal ubiquitin (Ub) by dehydroalanine we designed the diubiquitin (diUb) activity-based probe UbG76Dha-Ub (OTULIN activity-based probe [ABP]) that couples to the catalytic site of OTULIN and thereby captures OTULIN in its active conformation. The OTULIN ABP displays high selectivity for OTULIN and does not label other M1-cleaving DUBs, including CYLD. The only detectable cross-reactivities were the labeling of USP5 (Isopeptidase T) and an ATP-dependent assembly of polyOTULIN ABP chains via Ub-activating E1 enzymes. Both cross-reactivities were abolished by the removal of the C-terminal Gly in the ABP's proximal Ub, yielding the specific OTULIN probe UbG76Dha-Ub?G76 (OTULIN ABP?G76). Pull-downs demonstrate that substrate-bound OTULIN associates with the linear ubiquitin chain assembly complex (LUBAC). Thus, we present a highly selective ABP for OTULIN that will facilitate studying the cellular function of this essential DUB.

SUBMITTER: Weber A 

PROVIDER: S-EPMC5658516 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature