Western blotting was performed as described previously [21]. Proteins prepared in
Laemmli buffer were separated by SDS-PAGE, then transferred to PVDF membranes
(Bio-Rad Laboratories, USA) and blocked in 3% BSA. Membranes were probed with the
following primary antibodies. Total- and phospho-cJUN, glyceraldehyde 3-phosphate
dehydrogenase (GAPDH), total- and phospho-eukaryotic initiation factor 2α (eIF2α),
total- and phospho-AMP-activated protein kinase (AMPK), sirtuin 1 (Sirt1), total- and
phospho-acetyl-CoA carboxylase (ACC) and glucose-regulated protein 78 kDa (GRP78)
antibodies were purchased from Cell Signaling (USA). Total- and phospho-inositolrequiring
kinase 1 (IRE1) antibodies were obtained from Abcam (UK). C/EBP
homologous protein (CHOP) antibody was purchased from Santa Cruz (USA). Western
blot membranes were incubated with secondary antibodies from Santa Cruz (USA) that
were conjugated to horseradish peroxidase (HRP) and developed using enhanced
chemiluminescence HRP substrate from Perkin Elmer (USA). Images of the membranes
were taken with the ChemiDoc system and densitometry analysis was performed using
Image Lab software (Bio-Rad Laboratories, USA).