Transcriptional activator required for lipid homeostasis. Regulates transcription of the LDL receptor gene as well as the fatty acid and to a lesser degree the cholesterol synthesis pathway. Binds to the sterol regulatory element 1 (SRE-1) (5'-ATCACCCCAC-3'). Has dual sequence specificity binding to both an E-box motif (5'-ATCACGTGA-3') and to SRE-1 (5'-ATCACCCCAC-3'). Forms a tight complex with SCAP in the ER membrane. Efficient DNA binding of the soluble transcription factor fragment requires dimerization with another bHLH protein. Interacts with LMNA. Expressed in a wide variety of tissues, most abundant in liver and adrenal gland. In fetal tissues lung and liver shows highest expression. Isoform SREBP-1C predominates in liver, adrenal gland and ovary, whereas isoform SREBP-1A predominates in hepatoma cell lines. Isoform SREBP-1A and isoform SREBP-1C are found in kidney, brain, white fat, and muscle. Belongs to the SREBP family. 4 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Cellular Component: Golgi membrane; nucleoplasm; endoplasmic reticulum membrane; protein complex; endoplasmic reticulum; cytoplasm; integral to membrane; nuclear envelope; cytosol; nucleus
Molecular Function: protein dimerization activity; protein binding; sterol response element binding; DNA binding; sequence-specific DNA binding; protein complex binding; chromatin binding; protein kinase binding; transcription factor activity
Biological Process: circadian rhythm; response to drug; response to food; cholesterol metabolic process; response to retinoic acid; response to glucagon stimulus; response to cAMP; transcription, DNA-dependent; lipid biosynthetic process; positive regulation of cholesterol biosynthetic process; negative regulation of transcription from RNA polymerase II promoter; cellular lipid metabolic process; cellular response to starvation; negative regulation of insulin secretion; regulation of transcription from RNA polymerase II promoter; positive regulation of histone deacetylation; chemical signal regulation of heart rate; regulation of fatty acid metabolic process; response to glucose stimulus; insulin receptor signaling pathway; positive regulation of transcription from RNA polymerase II promoter; lipid metabolic process; response to progesterone stimulus; aging; lung development
LTP: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.