title: Molecular mechanisms of cellular cholesterol efflux.
abstract: Most types of cells in the body do not express the capability of catabolizing cholesterol, so cholesterol efflux is essential for homeostasis. For instance, macrophages possess four pathways for exporting free (unesterified) cholesterol to extracellular high density lipoprotein (HDL). The passive processes include simple diffusion via the aqueous phase and facilitated diffusion mediated by scavenger receptor class B, type 1 (SR-BI). Active pathways are mediated by the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1, which are membrane lipid translocases. The efflux of cellular phospholipid and free cholesterol to apolipoprotein A-I promoted by ABCA1 is essential for HDL biogenesis. Current understanding of the molecular mechanisms involved in these four efflux pathways is presented in this minireview.
authors: From the Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-5158 mcp3@mail.med.upenn.edu.
authors: Michael C
authors: MC
authors: Phillips
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000378:metabolism; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D001692:Biological Transport; D008076:Cholesterol, HDL / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D051122:Scavenger Receptors, Class B / Q000378:metabolism
chemical_list: C577836:ABCA1 protein, human; C419353:ABCG1 protein, human; D064286:ATP Binding Cassette Transporter 1; D000070998:ATP Binding Cassette Transporter, Subfamily G, Member 1; D018528:ATP-Binding Cassette Transporters; D008076:Cholesterol, HDL; C495124:SCARB1 protein, human; D051122:Scavenger Receptors, Class B
keywords: ABC Transporter; Cholesterol; Efflux; High Density Lipoprotein (HDL); Macrophage; Phospholipid; Plasma Membrane; Scavenger Receptor