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 .