Fig. 4. Enforced expression of WT, but not ubiquitinase-dead, MARCH8 decreases both endogenous (A and E) and exogenous PD-L1 levels (B-D) including cell surface PD-L1 levels (E).
A and E, HEK293T cells were transfected with the plasmids harboring different MARCH8 genes as indicated for 36 h. B-D, HEK293T cells were co-transfected with MARCH8 plus a plasmid expressing non-tagged PD-L1 (B) or tagged PD-L1 (C and D) for 36 or 48 h. Total cellular and cell surface PD-L1 were detected with Western blotting (A-D) and flow cytometry (E), respectively. LE, low exposure; EV, empty vector; NS, not significant; *, uncharacterized band generated by ectopic expression of PD-L1.