Fig. 3

Negative regulatory pathways of PD-L1 mediated by other posttranslational modifications. a MMP-7, MMP-9, and MMP-13 cleave the PD-1 binding domain of PD-L1, inhibiting T-cell apoptosis. b PD-L1 proteins undergo methylation by SET7 and demethylation by LSD2. c UFL1 or UFM1 enhances the UFMylation of PD-L1. d ISG15 associates with glycosylated PD-L1, promoting its ISGylation and accelerating the glycosylation-mediated degradation of PD-L1. e Cullin3 promotes NEDDylation, which contributes to the degradation of the PD-L1 protein. f GSH upregulates SERCA activity, suppressing the NF-κB signaling cascade and consequently the transcription of PD-L1. g CK2 induces phosphorylation of ING4, leading to the activation of ING4 and subsequent inhibition of the proteolytic degradation of PD-L1. The black arrows indicate positive regulation, and the red arrows indicate negative regulation