SREBPs: sterol-regulated transcription factors.

Studies of the feedback regulation of cholesterol synthesis in animals have led to the identification of a unique family of membrane-bound transcription factors, sterol regulatory element binding proteins (SREBPs) (Brown and Goldstein, 1997). In the presence of cholesterol, SREBPs are sequestered in the endoplasmic reticulum (ER). In the absence of a sterol signal, however, SREBPs undergo specific proteolytic events that lead to activation of distinct sets of target genes that control lipid metabolism. Characterization of this sterol-regulated pathway has revealed new paradigms for metabolic signal transduction.