FIGURE 5.

Degradation of endogenous CXCR4 in HeLa cells is disrupted by modulation of USP14 expression. A, HeLa cells transiently transfected with vector or HA-USP14 were treated with CXCL12 for 0, 3, 5, or 8 h as indicated. CXCR4 levels were detected by Western blot using an anti-CXCR4 antibody. Quantitation of relative amount of CXCR4 was determined by densitometric scanning as outlined under “Experimental Procedures.” Data obtained at time 0 and 8 h Data are mean ± S.E. from three independent experiments. ^*, p < 0.05; ^**, p < 0.01; ^***, p < 0.001 compared with control cells (no CXCL12 treatment, i.e. time 0); the data obtained at 3 and 5 h after CXCL12 incubation are from only two independent experiments, and thus statistical analyses were not performed for these time points. B, HeLa cells transiently transfected with scrambled siRNA (control) or USP14-specific siRNA were treated with CXCL12 for 0, 3, 5, or 8 h, as indicated. CXCR4 levels were detected by Western blot using an anti-CXCR4 antibody. Quantitation of relative amount of CXCR4 was determined by densitometric scanning as outlined under “Experimental Procedures.” Data are mean ± S.E. from three independent experiments. ^*, p < 0.05; ^**, p < 0.01.