LXR alpha

The ABCA1 molecule is a primary gatekeeper for regulating the intracellular transport of cholesterol. It belongs to a larger related multifamily of cAMP-dependent anion transporter cell membrane molecules. These key proteins are responsible for trafficking the reverse efflux of cholesterol from cells into peripheral tissues using the apolipoprotein A-1 (apo) carrier. In particular, the ABCA1 molecule exhibits a diverse expression profile and is found most highly expressed in macrophages.

Sterol-regulatory-element-binding protein 2 (SREBP2) is a transcription factor that regulates cholesterol homeostasis by controlling enzymes involved in cholesterol synthesis and uptake, e.g. HMG-CoA.

LXR Alpha, also known as Liver X receptor Alpha is a 50KDa protein that belongs to the nuclear hormone receptor family located in the nucleus. It is specifically expressed in the liver, kidney and intestine; however it has also been found in the spleen, macrophages and the adrenals. All of these tissues play an important role in lipid metabolism. The primary role of LXR Alpha is to maintain cholesterol homeostasis in macrophages by regulating the genes involved in this.

The ABCA1 (ATP-binding cassette transporter-A1) gene encodes a transmembrane protein, which plays a major role in phospholipid homeostasis by regulating cholesterol efflux from the cell. ABCA1 antibody studies have shown ABCA1 expression is up/down regulated by the transcription factors LXR and SREBP2 respectively.