B3GNT3 and neoplasm: A type II transmembrane protein B3GNT3 binds to and catalyzes PD-L1 N-linked glycosylation and B3GNT3 depletion inhibit tumor cell growth.492 COP9 signalosome (CSN) specific phosphorylation can target substrates to ubiquitin-dependent degradation.516 One of the family members CSN5 also possesses deubiquitination activity and positively regulates PD-L1.