SREBF1

Sterol regulatory element-binding protein 1 ;
SREBP-1 ;
Class D basic helix-loop-helix protein 1 ;
bHLHd1 ;
Sterol regulatory element-binding transcription factor 1 ;
[Cleaved into: Processed sterol regulatory element-binding protein 1]

alternative products:Additional isoforms seem to exist,function: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 (By similarity). 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').,online information:Sterol regulatory element-binding protein entry,PTM:At low cholesterol the SCAP/SREBP complex is recruited into COPII vesicles for export from the ER. In the Golgi complex SREBPs are cleaved sequentially by site-1 and site-2 protease. The first cleavage by site-1 protease occurs within the luminal loop, the second cleavage by site-2 protease occurs within the first transmembrane domain and releases the transcription factor from the Golgi membrane. Apoptosis triggers cleavage by the cysteine proteases caspase-3 and caspase-7.,sequence caution:Intron retention.,similarity:Belongs to the SREBP family.,similarity:Contains 1 basic helix-loop-helix (bHLH) domain.,subcellular location:Moves from the endoplasmic reticulum to the Golgi in the absence of sterols.,subunit: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.,tissue specificity: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.,

transcription, regulation of transcription, DNA-dependent, regulation of transcription from RNA polymerase II promoter,steroid metabolic process, cholesterol metabolic process, cellular response to starvation, positive regulation of biosynthetic process, response to extracellular stimulus, positive regulation of macromolecule biosynthetic process,positive regulation of macromolecule metabolic process, positive regulation of gene expression, sterol metabolic process, positive regulation of cellular biosynthetic process, response to nutrient levels, cellular response to extracellular stimulus, cellular response to nutrient levels, cellular response to stress, response to starvation,regulation of transcription, positive regulation of transcription, DNA-dependent, positive regulation of nucleobase, nucleoside, nucleotide and nucleic acid metabolic process, positive regulation of transcription, positive regulation of transcription from RNA polymerase II promoter, positive regulation of nitrogen compound metabolic process,regulation of RNA metabolic process, positive regulation of RNA metabolic process,

[Sterol regulatory element-binding protein 1]: Endoplasmic reticulum membrane ; Multi-pass membrane protein . Golgi apparatus membrane ; Multi-pass membrane protein . Cytoplasmic vesicle, COPII-coated vesicle membrane ; Multi-pass membrane protein . At high sterol concentrations, the SCAP-SREBP is retained in the endoplasmic reticulum. Low sterol concentrations promote recruitment into COPII-coated vesicles and transport of the SCAP-SREBP to the Golgi, where it is processed. .; [Processed sterol regulatory element-binding protein 1]: Nucleus .; [Isoform SREBP-1aDelta]: Nucleus .; [Isoform SREBP-1cDelta]: Nucleus .

Expressed in a wide variety of tissues, most abundant in liver and adrenal gland (PubMed:8402897). In fetal tissues lung and liver shows highest expression (PubMed:8402897). ; [Isoform SREBP-1A]: Predominates in hepatoma cell lines (PubMed:8402897). Also expressed in kidney, brain, white fat, and muscle (PubMed:8402897). ; [Isoform SREBP-1C]: Predominantly expressed in liver and adipose tissues (PubMed:8402897). Also expressed in kidney, brain, white fat, and muscle (PubMed:8402897).