Fig. 2: GSK3β is required for the control of ERRα stability by insulin.

a ERRα protein levels in HepG2 cells treated with either DMSO control or 10 μM of kinase specific-inhibitors SB 216763, CX-4945, PNU112455A, SB 202190 or CGP 74514A for 4 h. b ERRα protein levels in HepG2 cells transfected with 20 nM of either control, GSK3α or GSK3β siRNA for 72 h. c ERRα protein levels in 293T cells transfected with vectors expressing HA-GSK3β WT, constitutively active S9A mutant (CA), or kinase defective K85A mutant (KD) for 48 h. d Immunoblots (left, each lane represents liver from one mouse, n = 4 per group) and quantification (right) of ERRα protein levels in livers from GSK3β^f/f and GSK3β LKO mice. e ERRα protein levels and f mRNA levels of ESRRA and GSK3B (n = 3 per group) in HepG2 cells stably expressing either control shRNA or 2 distinct shRNAs targeting GSK3β. Cells were treated with 10 μg/ml insulin for 30 min after overnight serum starvation. g Western blots (left, each lane represents liver from one mouse, n = 3 per group) and quantification (right) of ERRα protein levels in livers from GSK3β LKO and their floxed littermates upon a fasting-refeeding transition. h Esrra and Gsk3b mRNA levels in control and GSK3β-null livers upon a fasting-refeeding transition (n = 4 per group). i 293T cells stably expressing either control or shRNA targeting GSK3β were transfected with HA-GSK3β WT, CA, or KD vectors for 48 h, cells were treated with 10 μg/ml insulin for 30 min after overnight serum starvation. j Proposed model of insulin-mediated stabilization of ERRα protein through the PI3K/AKT/ GSK3β pathway. Data are presented as means ± SEM, *p < 0.05, unpaired two-tailed Student’s t test (d, f–h). Source data are provided as a Source Data file.