Without a raft

摘要

The spatial organization of signalling proteins in the cell membrane is often ascribed to lipid-based 'rafts'. But single-molecule tracking reveals that such organization probably arises by protein-protein interactions. Signal transduction — the relay of signals from outside a cell to inside — frequently involves bewildering patterns of interactions between several different types of protein at the cell surface. Work attempting to make sense of this complexity suggests that specific lateral organization of the interacting proteins in the membrane is key to their signalling functions. But how is such organization generated? Work by Douglass and Vale, published in Cell, begins to provide some answers, and emphasizes the utility of recently developed single-molecule imaging techniques in addressing the dynamic properties of signalling networks. Moreover, the authors' experiments directly address the controversy over the mechanisms that generate localized variations in the composition of the cell membrane.