FIGURE 4.

SKIP regulates insulin-induced AS160 phosphorylation. A, effect of attenuation of SKIP in insulin-stimulated AS160 phosphorylation. C2C12 cells were transfected with the indicated siRNAs and stimulated with several concentrations of insulin (0–100 nm) for 10 min. Phosphorylation of AS160 at Thr-642 was measured by Western blot analysis and quantified by densitometry. Values are presented as mean ± S.E. (error bars). *, p < 0.05 (t test). B, co-localization of SKIP with GLUT4 at the membrane ruffles. C2C12 cells expressing GFP-SKIP and DsRed-GLUT4 were stimulated with insulin for 10 min. Cells were visualized by confocal microscopy. Enlarged images of boxed areas are shown in the lower panels. Yellow indicates regions of co-localization of SKIP and GLUT4 (arrowheads). Scale bar, 20 nm.