Besides the knowledge of chronic ER stress present in liver and adipose tissue in mouse models of obesity and obese humans,28, 41 recently, phosphorylation of eIF2alpha, an UPR signalling protein, was shown to be elevated in the context of NAFL and NASH in humans.37 Considering TUDCA's beneficial effects on ER stress,28 one would also expect changes in protein content and/or phosphorylation status of ER stress mediating membrane proteins after treatment with unconjugated UDCA. The gene discussed is EIF2S1; the disease is obesity due to melanocortin 4 receptor deficiency.