In addition, GRP78, the marker of ER stress, exhibits no difference in liver of Atf4−/− mice compared with wild-type mice either fed on a control diet or an HFD diet, suggesting that ER stress is not causal factors for ATF4-deficient protecting against HFD-induced NAFLD (Fig. S3A). This evidence concerns the gene ATF4 and metabolic dysfunction-associated steatotic liver disease.