FIGURE 5.

Adipocyte differentiation of ST2 cells is inhibited by overexpression of FAM57B. A, ST2 cells overexpressing FAM57B-FLAG were analyzed on day 6 of adipocyte differentiation by Western blotting using an anti-FLAG antibody. B, ST2 cells were infected with retroviruses expressing three different FAM57B variants. Three days after infection, adipogenesis was induced by replacing the medium with fresh medium containing an adipogenic mixture as indicated under “Experimental Procedures.” On day 6 of differentiation, the cells were fixed and stained with Oil Red O in which lipids are stained red, at a magnification of ×10. Scale bar, 100 μm. C, triglyceride (TG) content of ST2 cells expressing the FAM57B variants was analyzed on day 6 of adipogenesis. D, mRNA level of adipocyte markers was analyzed by qRT-PCR. E, we measured the Fam57b mRNA levels in ST2 cells overexpressing each FAM57B variant. F, ST2 cells overexpressing FAM57B var3 were treated with MG132 at the indicated concentrations for 6–12 h. The cells were harvested and subjected to Western blot analysis using anti-FLAG and anti-β-actin antibodies. Results are means ± S.D. (error bars) (n = 3); *, p < 0.05; **, p < 0.01; ***, p < 0.001.