Fig. 3

Rab37 regulates glycosylated PD-1 membrane presentation. A, B Confocal images of PD-1 (green) and Na⁺/K⁺ ATPase (red, PM marker) in COS-1 cells expressing GFP-WT-PD-1 or GFP-3NQ-PD-1. Scale bar: 10 μm. Colocalization of confocal images of PD-1 and Na⁺/K⁺ ATPase was determined (right). C, D COS-1 cells were transfected with either GFP-WT-PD-1 or GFP-3NQ-PD-1 plasmid followed by immunostaining of Calnexin (red, ER marker). Scale bar: 10 μm. Accumulation of calnexin at ER compartment was determined (right). E Annexin V/PI staining was performed at 48 h by flow cytometry in 293T cells and COS-1 cells. F, G Immunoblot analyses of sucrose gradient fractionations in Jurkat T cells after transfection with either GFP-WT-PD-1 or GFP-3NQ-PD-1 for 18 h. Calnexin and Na⁺/K⁺ ATPase proteins were blotted in addition to Rab37 and gPD-1. Protein intensity of PD-1^WT and PD-1^3NQ at fractions 4–12 was determined by image J and are indicated below the blots. The data are shown as the mean ± S.D. P values were determined by one-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001