SMILE inhibits CRTC2-induced gluconeogenic enzyme gene expression in hepatocytes.
A, AML12 cells were cotransfected with PEPCK-Luc, G6Pase-Luc, CRTC2, and SMILE expression vectors. B, primary hepatocytes were infected with Ad-GFP, Ad-CRTC2, and Ad-SMILE for 24 h, and gluconeogenic gene expression was analyzed by quantitative PCR. C, primary hepatocytes were infected with Ad-CRTC2 and Ad-SMILE for 24 h, and glucose output assay was performed using glucose-free media supplemented with gluconeogenic substrate sodium lactate (20 mmol/liter) and sodium pyruvate (1 mmol/liter). D, primary hepatocytes were infected with Ad-CRTC2, Ad-US, or Ad-shSMILE for 24 h and treated with insulin for 9 h. Glucose output assay was performed using glucose-free media supplemented with gluconeogenic substrate sodium lactate (20 mmol/liter) and sodium pyruvate (1 mmol/liter). Error bars show mean ± S.D. *, p < 0.05; ***, p < 0.005 by two-tailed Student's t test. n.s. means not significant. Results are representative of three independently performed experiments.