Fig. 7: PD-L1 homodimerization plays an important role in PD-1 binding and T-cell toxicity.
From: Homodimerized cytoplasmic domain of PD-L1 regulates its complex glycosylation in living cells
a PD-L1-Azi interaction with PD-1 was suppressed by 3RE mutation. Azi was incorporated at V76 of WT PD-L1 or PD-L1-3RE mutant. HEK293T cells were irradiated with UV in the absence or presence of PD-1-His protein. Shown are immunoblotting using anti-Flag and anti-His antibodies. b PD-L1△C suppressed WT PD-L1 cross-linking with PD-1. Cells expressing PD-L1-V76Azi-Flag or coexpressing PD-L1-V76Azi-Flag and PD-L1△C-Flag were incubated with PD-1-His protein. Covalent cross-linking was induced by UV treatment for 20 min. c, d T-cell mediated tumor cell killing assay in RKO KO PD-L1 cells expressing PD-L1 and PD-L1-3RE. Green fluorescent was counted as dead cells. Representative phases are shown. Scale bar, 100 μm. d The ratio of dead cells was quantified. N = 5. e Schematic diagram of PD-L1 homodimer function. All samples were treated with PNGase F to remove the N-glycan.
