Define Sterol Regulatory Element Binding Proteins (SREBPS)?

These belong to a general family of transcription factors. They are synthesized as membrane embedded proteins in response to depletion of cellar cholesterol.These proteins lead to the transcription of genes encoding the low density lipoprotein (LDL) receptor and multiple enzymes in the cholesterol and fatty acid biosynthetic pathways. Mammalian cells use a very sensitive mechanism to control the amount of cholesterol and fatty acids in their membranes. Recent evidence reveals that the steroid sensor in this system is another membrane embedded protein called SREBP cleavage activating protein (SCAP).