Protein: Sterol regulatory element binding protein sbp-1 (SREBP sbp-1) [Cleaved into: Processed sterol regulatory element binding protein sbp-1] (Q9XX00)
Organism: Caenorhabditis elegans
Function: Transcription factor involved in maintaining normal fat levels. Regulates the expression of genes involved in lipid metabolism in response to nutrient availability, such as the fatty-acid desaturases fat-5, fat-6 and fat-7. In response to a high-glucose diet, promotes fatty acid synthesis, elongation and desaturation, acting in concert with transcription factor mxl-3. Plays a role in synthesis of monomethyl branched-chain fatty acids (mmBCFAs) as well as other very-long-chain fatty acids. Downstream of the cis-Golgi membrane protein eas-1/GOLT1B and the E3 ubiquitin ligase rnf-145/RNF145, plays a role in the regulation of glial size, perhaps by modulating synthesis of long-chain polyunsaturated fatty-acids (LC-PUFA). Modulates expression of genes in the one-carbon cycle, which produces the methyl donor S-adenosylmethionine (SAM). Probably involved in a feedback loop in which decreased levels of SAM lead to increased transcriptional activity of sbp-1, thereby causing lipid accumulation. Involved in the negative regulation of zinc homeostasis. Involved in the response to simulated microgravity, in concert with Mediator complex subunit mdt-15, probably acting in the intestine. Plays a role in transgenerational lipid accumulation in response to a high-fat diet, probably acting by upregulating wdr-5.1 expression to increase the level of trimethylated 'Lys-4' histone H3 (H3K4me3), which may then induce the expression of fat-5, fat-6 and fat-7. May act as an oxygen sensor for lipid metabolism.
Subcellular location: Nucleus {ECO:0000269|PubMed:22035958, ECO:0000269|PubMed:28710073}. Note=Localization to nucleus is enhanced in a sams-1-dependent manner (PubMed:22035958). Localized to nucleus in an eas-1-dependent manner (PubMed:33370778). Nuclear localization is reduced by lowering the level of zinc (PubMed:28710073). Does not accumulate in the nucleus of AMsh glial cells during the early larval stages (L1 to L3), but has strong nuclear localization in adulthood (PubMed:33370778). {ECO:0000269|PubMed:22035958, ECO:0000269|PubMed:28710073, ECO:0000269|PubMed:33370778}.; SUBCELLULAR LOCATION: [Sterol regulatory element binding protein sbp-1]: Endoplasmic reticulum membrane {ECO:0000250|UniProtKB:Q9WTN3}; Multi-pass membrane protein {ECO:0000255}.; SUBCELLULAR LOCATION: [Processed sterol regulatory element binding protein sbp-1]: Nucleus {ECO:0000255|PROSITE-ProRule:PRU00981}.
Interaction partners:
- Mediator of RNA polymerase II transcription subunit 15
- Sterol regulatory element-binding protein cleavage-activating protein
- Nuclear hormone receptor family member nhr-49
- 3-hydroxy-3-methylglutaryl coenzyme A reductase
- Importin N-terminal domain-containing protein
- Delta
- Membrane-bound transcription factor site-2 protease
- Delta
- NPC intracellular cholesterol transporter 1 homolog 1
- Delta
Sequence:
MNEEFEGDVPMSDPFLSLVTKLDDIAPFPNNDPLDFDMEHNWQEPGPSQQPDPSIPGNQHSPPQEYYDIDGQRDVSTLHSLLNHNNDDFFSMRFSPPNFDLGGGRGPSLAATQQLSGEGPASMLNPLQTSPPSGGYPPADAYRPLSLAQQLAAPAMTPHQAASLFVNTNGIDQKNFTHAMLSPPHHTSMTPQPYTEAMEHINGYMSPYDQAQGPSGPSYYSQHHQSPPPHHHHHHPMPKIHENPEQVASPSIEDAPETKPTHLVEPQSPKSPQNMKEELLRLLVNMSPSEVERLKNKKSGACSATNGPSRSKEKAAKIVIQETAEGDEDEDDEDSDSGETMSQGTTIIVRRPKTERRTAHNLIEKKYRCSINDRIQQLKVLLCGDEAKLSKSATLRRAIEHIEEVEHENQVLKHHVEQMRKTLQNNRLPYPEPIQYTEYSARSPVESSPSPPRNERKRSRMSTTTPMKNGTRDGSSKVTLFAMLLAVLIFNPIGLLAGSAIFSKAAAEAPIASPFEHGRVIDDPDGTSTRTLFWEGSIINMSYVWVFNILMIIYVVVKLLIHGDPVQDFMSVSWQTFVTTREKARAELNSGNLKDAQRKFCECLATLDRSLPSPGVDSVFSVGWECVRHLLNWLWIGRYIARRRRSTTKPVSVVCRSHAQTAVLYHEIHQLHLMGITGNFEDTYEPSALTGLFMSLCAVNLAEAAGASNDGLPRAVMAQIYISASIQCRLALPNLLAPFFSGYFLRRARRHVRRAPEHSVSHLLWIFHPATRKFMSDAKRLEHVLSSKQKQLRFGSFVEDEQLSPLARIRTTLKVYLLSKLVQELVGGDEIFTKNVERILNDNDRLDDEVDVVDVSRLLVTISTQCAAILTNEKDESAKFGTWISRNGDACCTWWTHVLTCGIYWRSNKNELARQHYSLIRNCPPKILTDNLGLAVGHALCARKICIDDRDSPKVSQYVCIHTKKSLESLRLFSTSSRASGVVSGIQEGTRRMAYEWIMNSLLDAWRSNLFASKPYWTQSFKGQSTFSTLYQEAYNHYAIINGTRGDCWRLFVYELTCRMLNGANPQATWSGVRRVRSTKMDAVRGRVSMRRSAQPDAFHLHTLVKLHTSMDL