Biochemical analysis of PD-L1 ubiquitination by CRL3^SPOP, ARIH1, and NEDD4 family ubiquitin ligases.

ABSTRACT: As a key immune checkpoint ligand, PD-L1 is a critical target in cancer immunotherapy. While multiple E3 ubiquitin ligases including CRL3^SPOP, ARIH1, and NEDD4 have been implicated in PD-L1 degradation, the precise enzymatic mechanisms remain unclear. In this study, we systematically compared the enzymatic activities of CRL3^SPOP, ARIH1, and NEDD4 ligases toward the cytoplasmic domain of PD-L1 through in vitro reconstitution with purified components. ARIH1, rather than CRL3^SPOP, independently ubiquitinates PD-L1. We reveal a mechanism where ARIH1 acts as a substrate receptor and cooperates with CRLs to catalyze PD-L1 ubiquitination. We also biochemically validated the E3 ligase activity of the NEDD4 family E3s toward PD-L1. By using liposomes in the enzymati

SUBMITTER: Xie G 

PROVIDER: S-EPMC12335357 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature