FIG. 4.

Nbr1 traps EGFR on the cell surface and inhibits its degradation. All error bars represent SEM. P values were calculated by a nonpaired t test (n = 5 cells under each condition) (*, P < 0.05; **, P < 0.01; ***, P < 0.001). (A) HeLa cells were transfected with EGFR-GFP, with or without Myc-Nbr1, and subjected to live-cell imaging by epifluorescence microscopy for 30 min following the addition of EGF (50 ng/ml). A nonstimulated control was also included (bottom). Scale bars, 10 μm. (B) Quantification of the number of EGFR-GFP-internalizing spots per area. The overexpression of Myc-Nbr1 induces a delay of 8 min in EGFR internalization. (C) Normalized total EGFR-GFP fluorescence from whole-cell areas. The overexpression of Myc-Nbr1 abrogates the degradation of EGFR.