SREBPs: activators of the complete program of cholesterol and fatty acid synthesis in the liver

Lipid homeostasis in vertebrate cells is regulated by a family of membrane-bound transcription factors designated sterol regulatory element-binding proteins (SREBPs).SREBPs directly activate the expression of more than 30 genes dedicated to the synthesis and uptake of cholesterol, fatty acids, triglycerides, and phospholipids, as well as the NADPH cofactor required to synthesize these molecules (1-4).In the liver, three SREBPs regulate the production of lipids for export into the plasma as lipoproteins and into the bile as micelles.The complex, interdigitated roles of these three SREBPs have been dissected through the study of ten different lines of gene-manipulated mice.These studies form the subject of this review.