Revitalizing membrane rafts: new tools and insights

Key Points Ten years ago, the lipid raft field was suffering from ambiguous methodology and imprecise nomenclature. New high-resolution imaging methods are now giving insights into raft dynamics. Together with other studies, this has led to changes in our concept of rafts. Rafts in plasma membranes can be characterized by three different states: dynamic nanoscale assemblies, raft platforms stabilized by oligomerization and micrometre-scale phase separation. Lipidomics is beginning to give comprehensive views of the lipid composition of raft domains. Three examples of roles that rafts have in cellular function are: T cell signalling, HIV assembly and membrane trafficking. A key open issue for the field is how lipids interact with integral raft proteins. Ten years ago, the cell biological role of lipid rafts was controversial owing to limited methodology and confusing nomenclature. Through technical advances, our concept of lipid rafts has evolved into that of dynamic nanoscale assemblies that can be stabilized to control signalling and membrane trafficking. Ten years ago, we wrote a Review on lipid rafts and signalling in the launch issue of Nature Reviews Molecular Cell Biology . At the time, this field was suffering from ambiguous methodology and imprecise nomenclature. Now, new techniques are deepening our insight into the dynamics of membrane organization. Here, we discuss how the field has matured and present an evolving model in which membranes are occupied by fluctuating nanoscale assemblies of sphingolipids, cholesterol and proteins that can be stabilized into platforms that are important in signalling, viral infection and membrane trafficking.