Organisation and dynamics of antigen receptors: implications for lymphocyte signalling

In contrast to the fluid mosaic model proposed by Singer and Nicolson over thirty years ago, the emergent paradigm is one of plasma membrane compartmentalisation mediated by protein–protein interactions, differences in lipid composition, and interactions with the underlying actin cytoskeleton. Extensive research has focused on examining the distribution and organisation of cell surface receptors upon ligand binding; however, relatively little is known about the steady-state organisation and dynamics of cell surface proteins. Here, we discuss recent findings on the regulation of steady-state organisation and diffusion dynamics of immunoreceptors, and how this might impact on our understanding of basal and ligand-dependent signalling.