FIGURE 3.

Contributions of CREB and TORC2 to AMPK-, SIK1-, and GSK3β-mediated suppressions of CRE activity. HepG2 cells were cotransfected with the expression plasmids for GAL4-truncated CREB (bZIP domain) (0.25 μg) or GAL4-truncated TORC2 (coiled coil region) (0.25 μg) and a pTAL-5× UAS reporter plasmid (0.25 μg) with the internal reporter pRL-TK (0.03 μg) (A and B). HepG2 cells were serum-starved overnight before incubation with AICAR (2 mm), insulin (10 nm), and GSK3β inhibitor or SB-415286 (30 μm) with or without 10 μm forskolin. Adenovirus (Ad)-mediated overexpressions of SIK1 proteins were detected using an anti-SIK1 immunoblot (lower panel). The specific transactivation activities of TORCs were expressed as the -fold activation of the empty Gal4 vector, pM. Means and S.D. are indicated (n = 3). *, p < 0.05.