FIGURE 3.

SiRNA silencing of HUWE1 and NEDD4-1 increases ABCG1 protein expression. A, CHO-K1 cells overexpressing ABCG1 were transfected with control siRNA, siRNAs for HUWE1 or NEDD4-1 individually, or both as described under “Experimental Procedures.” Cells were harvested and proteins separated via SDS-PAGE followed by immunoblotting with the indicated antibodies. Immunoblots are representative of four independent experiments with similar results. Bar graphs represent quantification of ABCG1 protein relative to tubulin, of four independent experiments (average ± S.E.), performed in duplicate cultures, with * indicating p < 0.05 compared with Control. B, CHO-K1 cells overexpressing ABCG1 were transfected with alternate primers as described under A. Results are representative of two independent experiments. C, ABCG1 monomer as well as dimer after siRNA treatment as described under A.