English: When sterol levels are high in the endoreticulum (ER), SREBP, SCAP and INSIG form a stable complex. When sterol levels drop, SCAP dissociate from INSIG and escorts SREBP into the Golgi apparatus, where two proteases, S1P and S2P, act sequentially to release the N-terminal bHLH domain of SREBP. The SREBP bHLH domain enters the nucleus to activate the transcription of genes with SREBP-responsive elements (SRE). Genes regulated by SREBP usually function to increase cellular sterol content, including the genes involved in sterol synthesis and the uptake of low-density lipoprotein (LDL).