Oxysterols regulate cholesterol homeostasis through liver X receptor (LXR) and sterol regulatory element binding protein (SREBP) mediated signaling pathway. Insig1 is an insulin-induced gene. It encodes an endoplasmic reticulum (ER) membrane protein that plays a critical role in regulating cholesterol concentrations in cells. Insig1 binds to the sterol-sensing domains of SREBP cleavage-activating protein (SCAP) and HMG CoA reductase, and is essential for the sterol-mediated trafficking of the two proteins. It may also play a role in growth and differentiation of tissues involved in metabolic control, and may play a regulatory role during G0/G1 transition of cell growth.