HDL and Scavenger Receptor Class B Type I (SRBI).

The scavenger receptor class B type I (SR-BI) is a versatile HDL receptor protein. It is highly expressed in liver and steroidogenic tissues. SR-BI regulates selective uptake of cholesterol ester (CE) from HDL, revealing its role in mediating reverse cholesterol transport (RCT) and steroid hormone synthesis. In addition, SR-BI is involved in cholesterol transport, cellular inflammatory response, platelet reactivity, and HDL-initiated signaling in the vascular system in several mouse models. Mutations in the human SR-BI gene (SCARB1) have been found to be associated with abnormally high plasma HDL-C levels and an increased risk of atherosclerotic cardiovascular disease. At present, the key regions of SR-BI transmembrane structure and the regulatory mechanisms of SR-BI expression still need to be further studied. In this chapter, the structural, functional, and regulatory characteristics of SR-BI are reviewed, and the importance of SR-BI in related metabolic diseases was expounded.