Overexpression of the ER stress chaperone BIP (GRP78) in ob/ob mice (as with Ildr2) reverses hepatic steatosis [51], and hypomorphic expression of UPR modulators Atf6, Ire1α, Chop, and Crebh in mouse models cause hepatic dyslipidemia [32], [33], [52], [53]. Here, ATF6 is linked to fatty liver disease.