HSPA5 and metabolic dysfunction-associated steatotic liver disease: During ER stress, activating transcription factor 6 (ATF6) is activated following release from the ER chaperone, Grp78/BiP (BiP), which mediates the expression of UPR target genes, including XBP1. Although previous studies have shown the possible role of ER stress in NAFLD (Kim et al., 2018), the specific mechanism remains largely unknown.