INSIG SREBP1A/1C/2 is retained in the endoplasmic reticulum by SCAP:cholesterol:INSIG Authored: May, B, 2012-06-10 Edited: May, B, 2012-06-10 Reactome Database ID Release 432317530 Reactome, http://www.reactome.org ReactomeREACT_147892 Reviewed: Liang, Guosheng, 2012-08-25 SREBF1A/1C/2 is retained in the endoplasmic reticulum by SCAP:cholesterol:INSIG SREBPs (SREBP1A/1C/2, SREBFs) bind SCAP in the endoplasmic reticulum membrane. Luminal loop 1 of SCAP binds cholesterol which prevents SCAP from interacting with Sec24 in the CopII coat complex and allows SCAP to interact with INSIG instead. These interactions retain SCAP:SREBP1A/1C/2 in the endoplasmic reticulum. The order of assembly of the SREBP1A/1C/2:SCAP:cholesterol:INSIG complex is unknown. has a Stoichiometric coefficient of 4 SREBP1A/1C/2:SCAP:cholesterol:INSIG SREBP1A/1C/2:SCAP