Summary

Name INSIG1
Full Name Insulin-induced gene 1 protein
Synonyms INSIG-1 |
Primary ID O15503
Links - -
Type protein
Relations 3
Function Oxysterol-binding protein that mediates feedback control of cholesterol synthesis by controlling both endoplasmic reticulum to Golgi transport of SCAP and degradation of HMGCR (PubMed:12202038, PubMed:12535518, PubMed:16168377, PubMed:16399501, PubMed:16606821, PubMed:32322062). Acts as a negative regulator of cholesterol biosynthesis by mediating the retention of the SCAP-SREBP complex in the endoplasmic reticulum, thereby blocking the processing of sterol regulatory element-binding proteins (SREBPs) SREBF1/SREBP1 and SREBF2/SREBP2 (PubMed:12202038, PubMed:16399501, PubMed:32322062). Binds oxysterol, including 25-hydroxycholesterol, regulating interaction with SCAP and retention of the SCAP-SREBP complex in the endoplasmic reticulum (PubMed:32322062). In presence of oxysterol, interacts with SCAP, retaining the SCAP-SREBP complex in the endoplasmic reticulum, thereby preventing SCAP from escorting SREBF1/SREBP1 and SREBF2/SREBP2 to the Golgi (PubMed:15899885, PubMed:32322062). Sterol deprivation or phosphorylation by PCK1 reduce oxysterol-binding, disrupting the interaction between INSIG1 and SCAP, thereby promoting Golgi transport of the SCAP-SREBP complex, followed by processing and nuclear translocation of SREBF1/SREBP1 and SREBF2/SREBP2 (PubMed:32322062). Also regulates cholesterol synthesis by regulating degradation of HMGCR

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Modifications Tables

Relations

Regulator Mechanism target score
+ up-regulates quantity by stabilization img/direct-activation.png phosphorylation INSIG1 0.259
Publications: 1 Organism: Homo Sapiens
+ down-regulates activity img/direct_inhibition.png binding SCAP 0.759
Publications: 1 Organism: Cricetulus Griseus
+ down-regulates quantity img/direct_inhibition.png ubiquitination INSIG1 0.49
Publications: 1 Organism: Homo Sapiens