INSIG1 — Insulin induced gene 1

INSIG1 belongs to a gene co-expression module in 8 of 28 SCUBA cell types. Each module groups genes that rise and fall together in that cell type; the genes it shares a module with are its closest co-expression partners there.

INSIG1's module in each cell type

About the gene

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. 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. Binds oxysterol, including 25-hydroxycholesterol, regulating interaction with SCAP and retention of the SCAP-SREBP complex in the endoplasmic reticulum. 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. 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. Also regulates cholesterol synthesis by regulating degradation of HMGCR: initiates the sterol-mediated ubiquitin-mediated endoplasmic reticulum-associated degradation (ERAD) of HMGCR via recruitment of the reductase to the ubiquitin ligases AMFR/gp78 and/or RNF139. Also regulates degradation of SOAT2/ACAT2 when the lipid levels are low: initiates the ubiquitin- mediated degradation of SOAT2/ACAT2 via recruitment of the ubiquitin ligases AMFR/gp78.

Human Protein Atlas · Open Targets · UniProt

Gene annotation from the Human Protein Atlas and UniProt; see sources & licences.