Anti-INSIG1 antibodies are used in the immunodetection of the protein insulin induced gene 1. In humans, the canonical protein has a reported length of 277 amino acid residues and a mass of 30 kDa. Its subcellular localization is in the ER. Alternative splicing is reported to yield 2 different isoforms for this protein. It is reported to be expressed in all tissues tested with highest expression in the liver. A member of a the INSIG protein family, INSIG1 is reported to be an oxysterol-binding protein that mediates feedback control of cholesterol synthesis by controlling both endoplasmic reticulum to Golgi transport of SCAP and degradation of HMGCR. Post-translational modifications have been described, including ubiquitination and phosphorylation. Synonyms for this target antigen include insulin-induced gene 1 protein, INSIG-1 membrane protein, and CL6.