SREBF1, also named as BHLHD1 and SREBP1, contains one basic helix-loop-helix (bHLH) domain and belongs to the SREBP family. It is a transcriptional activator required for lipid homeostasis. The SREBPs are synthesized as precursors anchored to endoplasmic reticulum (ER) membranes and complexed with SCAP. When the cellular cholesterol level is low, SREBP-SCAP complexes move to the Golgi apparatus, where SREBPs undergo a two-step proteolytic processing, leading to the release of the mature form, an N-terminal fragment, i.e, basic helix-loop-helix leucine zipper transcription factor. These factors enter the nucleus where they bind to sterol regulatory elements (SRE) in the promoter regions of a number of genes whose products mediate the synthesis of cholesterol and fatty acids. [PMID: 21698267].