Lipid rafts (membranes)

Article By:

Fielding, Christopher J. Cardiovascular Research Institute, University of California Medical Center, San Francisco, California.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.800820

Microdomains of the cell surface that play key roles in promoting information transfer across the membrane bilayer. The plasma membrane is composed of a lipid bilayer into which are inserted various essential proteins, such as transmembrane ion-channel and transporter proteins (which allow for the movement of small molecules into and out of the cell) and signaling proteins. Many of these proteins are found associated with domains on the surface of the membrane that are rich in free cholesterol (FC) and sphingolipids (lipids containing the amino acid sphingosine or its derivatives); some lipid components of transmembrane signaling pathways are also found here. It seems likely that both leaflets of the bilayer contribute to the structure of the microdomains. It is also evident that these rafts consist of a mixture of two quite different types of FC- and sphingolipid-rich domains: bowl-shaped caveolae and flat lipid rafts. Both caveolae and lipid rafts act as assembly sites (scaffolds) for signaling complexes, and may have important roles in signal transduction and other crucial intracellular functions. See also: Cell (biology); Cell membrane; Protein

The content above is only an excerpt.