INSIG1 Antibody – Rabbit Polyclonal

Oxysterols regulate cholesterol homeostasis through the liver X receptor (LXR)- and sterol regulatory element-binding protein (SREBP)-mediated signaling pathways. This gene is an insulin-induced gene. It encodes an endoplasmic reticulum (ER) membrane protein that plays a critical role in regulating cholesterol concentrations in cells. This protein 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. Alternatively spliced transcript variants encoding distinct isoforms have been observed. [provided by RefSeq, Jun 2009]

INSIG1: Mediates feedback control of cholesterol synthesis by controlling SCAP and HMGCR. Functions by blocking the processing of sterol regulatory element-binding proteins (SREBPs). Capable of retaining the SCAP-SREBF2 complex in the ER thus preventing it from escorting SREBPs to the Golgi. Initiates the sterol-mediated ubiquitin-mediated endoplasmic reticulum-associated degradation (ERAD) of HMGCR via recruitment of the reductase to the ubiquitin ligase, AMFR/gp78. May play a role in growth and differentiation of tissues involved in metabolic control. May play a regulatory role during G0/G1 transition of cell growth. Belongs to the INSIG family.

Protein type: Membrane protein, integral; Membrane protein, multi-pass

Chromosomal Location of Human Ortholog: 7q36

Cellular Component: endoplasmic reticulum; endoplasmic reticulum membrane

Molecular Function: protein binding

Biological Process: cell proliferation; cholesterol biosynthetic process; inner ear morphogenesis; metabolic process; middle ear morphogenesis; negative regulation of fat cell differentiation; negative regulation of fatty acid biosynthetic process; palate development; SREBP-mediated signaling pathway; triacylglycerol metabolic process