Caveolin, sterol carrier protein-2, membrane cholesterol-rich microdomains and intracellular cholesterol trafficking.
While the existence of membrane lateral microdomains has been known for over 30 years, interest in these structures accelerated in the past decade due to the discovery that cholesterol-rich microdomains serve important biological functions. It is increasingly appreciated that cholesterol-rich microdomains in the plasma membranes of eukaryotic cells represent an organizing nexus for multiple cellular proteins involved in transmembrane nutrient uptake (cholesterol, fatty acid, glucose, etc.), cell-signaling, immune recognition, pathogen entry, and many other roles. Despite these advances, however, relatively little is known regarding the organization of cholesterol itself in these plasma membrane microdomains. Although a variety of non-sterol markers indicate the presence of microdomains in the plasma membranes of living cells, none of these studies have demonstrated that cholesterol is enriched in these microdomains in living cells. Further, the role of cholesterol-rich membrane microdomains as targets for intracellular cholesterol trafficking proteins such as sterol carrier protein-2 (SCP-2) that facilitate cholesterol uptake and transcellular transport for targeting storage (cholesterol esters) or efflux is only beginning to be understood. Herein, we summarize the background as well as recent progress in this field that has advanced our understanding of these issues.
Schroeder
Friedhelm
F
Department of Physiology and Pharmacology, Texas A&M University, TVMC College Station, TX, 77843-4466, USA. fschroeder@cvm.tamu.edu
Huang
Huan
H
McIntosh
Avery L
AL
Atshaves
Barbara P
BP
Martin
Gregory G
GG
Kier
Ann B
AB
D000818:Animals; D001646:Bile / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D022461:Caveolins / Q000378:metabolism*; D002462:Cell Membrane / Q000502:physiology; D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins / Q000502:physiology; D031541:Fluorescence Resonance Energy Transfer; D005677:G(M1) Ganglioside / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D010750:Phosphoproteins / Q000502:physiology; D033921:Vesicular Transport Proteins / Q000502:physiology; D000098682:Steroidogenic Acute Regulatory Protein
D002352:Carrier Proteins; D022461:Caveolins; D050556:Fatty Acid-Binding Proteins; D008563:Membrane Lipids; D008565:Membrane Proteins; D010750:Phosphoproteins; D033921:Vesicular Transport Proteins; D000098682:Steroidogenic Acute Regulatory Protein; C072087:sterol carrier proteins; D005677:G(M1) Ganglioside; D002784:Cholesterol