SCARB1

Scavenger receptor class B member 1 (SRB1) also known as SR-BI is a is_associated_with::protein that in humans is encoded by the SCARB1 is_associated_with::gene. SR-BI functions as a receptor for is_associated_with::high-density lipoprotein.

is_associated_with::Scavenger receptor class B, type I (SR-BI) is an is_associated_with::integral membrane protein found in numerous cell types/tissues, including the is_associated_with::liver and is_associated_with::adrenal. It is best known for its role in facilitating the uptake of cholesteryl esters from is_associated_with::high-density lipoproteins in the liver. This process drives the movement of is_associated_with::cholesterol from peripheral tissues towards the is_associated_with::liver for excretion. This movement of is_associated_with::cholesterol is known as is_associated_with::reverse cholesterol transport and is a protective mechanism against the development of is_associated_with::atherosclerosis, which is the principal cause of is_associated_with::heart disease and is_associated_with::stroke.

SR-BI has also been identified in the livers of non-mammalian species (is_associated_with::turtle, is_associated_with::goldfish, is_associated_with::shark, is_associated_with::chicken, is_associated_with::frog, and skate), suggesting it emerged early in vertebrate evolutionary history. The turtle also seems to upregulate SB-RI during egg development, indicating that cholesterol efflux may be at peak levels during developmental stages.

In melanocytic cells SCARB1 gene expression may be regulated by the MITF.

SCARB1 is, along with is_associated_with::CD81, the receptor for the entry of the is_associated_with::Hepatitis C virus in liver cells.