SREBF1

SREBF1

A gene on chromosome 17p11.2 that encodes a basic helix-loop-helix-leucine zipper (bHLH-Zip) transcription factor, which binds to the sterol regulatory element-1 (SRE1), a decamer flanking the low-density lipoprotein receptor gene and genes involved in sterol biosynthesis. The protein is synthesised as a precursor attached to the nuclear membrane and endoplasmic reticulum; once cleaved, the mature protein translocates to the nucleus and activates transcription by binding to the SRE1. Sterols inhibit precursor cleavage; the mature nuclear form is rapidly catabolised, reducing transcription.