LIPID RAFTS, CAVEOLAE, AND THEIR ENDOCYTOSIS

Lipid rafts are plasma membrane microdomains enriched in cholesterol and sphingolipids that are involved in the lateral compartmentalization of molecules at the cell surface. Internalization of ligands and receptors by these domains occurs via a process defined as raft-dependent endocytosis. Caveolae are caveolin-1-enriched smooth invaginations of the plasma membrane that form a subdomain of lipid rafts. Endocytosis of rafts, including caveolar but also noncaveolar dynamin-dependent and dynamin-independent pathways, is characterized by its cholesterol sensitivity and clathrin-independence. In this review we will characterize lipid rafts and caveolae, their endocytosis and its regulation by the actin cytoskeleton, caveolin-1, dynamin, and cholesterol.