Sterol regulatory element-binding protein 1 (SREBP1) (SREBP1)

Sterol regulatory element-binding protein 1 (SREBP1) is a key transcription factor that masterminds the synthesis of fatty acids, triglycerides, and phospholipids (UniProt: P36956). It exists in two primary isoforms, SREBP-1a and SREBP-1c, which are synthesized as inactive precursors tethered to the endoplasmic reticulum (ER) membrane. When cellular lipid levels are low, the SREBP-cleavage activating protein (SCAP) escorts SREBP1 to the Golgi apparatus, where it undergoes sequential proteolytic cleavage by Site-1 and Site-2 proteases to release its transcriptionally active N-terminal domain (PubMed: 28430630). This active fragment enters the nucleus to activate genes like Fatty Acid Synthase (FASN), providing the building blocks for cell membranes and energy storage. In pathological states, SREBP1 is frequently overactivated, contributing to the development of metabolic disorders such as Nonalcoholic Steatohepatitis (NASH) and insulin resistance (NIH: PMC4705051). Beyond metabolic disease, SREBP1 is highly upregulated in various cancers (including prostate, breast, and glioblastoma) to satisfy the increased lipid demand required for rapid cell proliferation and signaling (PubMed: 32801449). Current drug discovery efforts focus on small molecules that prevent the ER-to-Golgi translocation or inhibit the proteases required for maturation. However, targeting this pathway presents challenges due to the risk of disrupting physiological lipid balance and the potential for compensatory metabolic adaptations (PubMed: 30206110).

Other names

SREBP-1Sterol regulatory element-binding transcription factor 1SREBF1Basic helix-loop-helix-leucine zipper transcription factorBHLHD1

Inhibition of SREBP1 translocation from the endoplasmic reticulum to the Golgi apparatus; Inhibition of proteolytic cleavage by Site-1 and Site-2 proteases; Inhibition of SCAP-SREBP complex formation; Direct antagonism of transcriptional activity.