Insig2 is highly similar to the protein product encoded by gene Insig1. Both Insig1 protein and Insig2 protein are endoplasmic reticulum proteins that block the processing of sterol regulatory element binding proteins (SREBPs) by binding to SREBP cleavage-activating protein (SCAP), and thus prevent SCAP from escorting SREBPs to the Golgi.
