Fig 1: GSK3ß-mediated ERRa degradation is dependent on FBXW7.a Devised stratagem to identify and validate E3 ligase(s) targeting ERRa. See also Supplementary Fig. 4a. b High-affinity CPD motifs presented in previously established FBXW7 substrates including PGC-1a, c-Myc, SREBP1a, and REV-ERBa. Schematic of the two putative CPD motifs identified in ERRa spanning from residues serine 19 to serine 26, phosphorylated sites are highlighted c Co-IP of endogenous ERRa and FBXW7 in HepG2 cells treated with MG132. d Co-IP and reciprocal co-IP were performed using lysates from 293T cells transiently co-expressing V5-FBXW7 and Flag-ERRa WT or 3SA mutant. e Ubiquitination levels of ERRa WT or 3SA mutant in HEK293T cells transiently co-expressing the indicated constructs, cells were treated with MG132 prior to collection. f Protein levels of ERRa WT or 3SA in the presence or absence of FBXW7 in HEK293T cells. g HEK293T cells were co-transfected with the indicated constructs for 36 h prior to treatment with protein synthesis inhibitor cycloheximide (CHX, 100 µg/ml) for the indicated times. h Co-IP of endogenous ERRa and FBXW7 in GSK3ß-silenced HepG2 cells treated with MG132. i Co-IP of FBXW7 and ERRa in HEK293T cells transiently transfected with HA-GSK3ß WT or CA mutant. Cells were treated with MG132 prior to collection. j V5-FBXW7 and empty vectors were transiently transfected into HEK293T cells stably expressing either control or shRNAs targeting GSK3ß. k Immunoblots (left, each lane represents liver from one mouse, n = 3 per group) and quantification (right) of ERRa protein levels in control and FBXW7-null livers during the fasting-refeeding transition. l Esrra and Fbxw7 mRNA levels in control and FBXW7-null livers upon a fasting-refeeding transition (n = 5 per group). Data are presented as means ± SEM, *p < 0.05, unpaired two-tailed Student’s t test (k, l). Source data are provided as a Source Data file.