Have we become overly reliant on lipid rafts? Talking Point on the involvement of lipid rafts in T-cell activation.

During the past decade, the lipid-raft hypothesis has focused attention on the role of membrane domains in controlling cellular functions. Among the best-studied roles of lipid rafts is the regulation of T-cell signalling. In particular, a model has emerged in which lipid rafts regulate protein-protein interactions during signalling in a cholesterol-dependent manner. Does this model provide the best description of what is happening in living cell membranes? Alternatively, has our ability to evaluate this question critically become compromised by the influential nature of the lipid-raft model itself? Here, this issue is explored in the context of two of the major tenets of the lipid-raft model.