The differential miscibility of lipids as the basis for the formation of functional membrane rafts

The formation of sphingolipid-cholesterol microdomains in cellular membrane s has been proposed to function in sorting and transport of lipids and prot eins as well as in signal transduction. An increasing number of cell biolog ical and biochemical studies now supports this concept. Here we discuss the structural properties of lipids in a cell biological context. The sphingol ipid-cholesterol microdomains or rafts are described as dispersed liquid or dered phase domains. These domains are dynamic assemblies to which specific proteins are selectively sequestered while others are excluded. The protei ns associated to rafts can act as organizers and can modulate raft size and function. (C) 1998 Elsevier Science B.V. All rights reserved.