Are rafts involved in T‐cell receptor signalling?: Introduction to the Talking Point on the involvement of lipid rafts in T‐cell activation

Lipid rafts are envisioned as cell‐membrane domains with distinctive physical properties and lipid compositions. Their existence and proposed functions in cellular processes are a matter of intense debate. Raft involvement at T‐cell receptor (TCR) activation sites in the plasma membrane is an intense focus of the research community. In the accompanying Talking Points in this issue of EMBO reports , Anne Kenworthy and Hai‐Tao He & Didier Marguet present differing views on this topic, debating both the existence of lipid rafts and their contribution to T‐cell triggering (He & Marguet, 2008; Kenworthy, 2008). The membranes of eukaryotic cells contain a complex mixture of glycerophospholipids, sphingolipids and cholesterol, and the chemistry of these lipid species has profound effects on the physical properties of the membrane. The phosphoglycerate backbones of different glycerophospholipids harbour the different functional head groups bound to the phosphate. The two remaining hydroxyl groups are esterified by acyl chains of varying lengths and degrees of saturation. Sphingolipids contain the aliphatic amino‐alcohol sphingosine, which is coupled to …