Transmembrane adaptor proteins:: Organizers of immunoreceptor signalling

Signalling through multichain immunoreceptors is required for the development, activation and differentiation of haematopoietic cells. One of the most challenging questions with regard to these processes is how immunoreceptor-mediated signals are converted into appropriate cellular responses. The recent identification of a novel group of signalling molecules, known as transmembrane adaptor proteins, has led to exciting new insights. The transmembrane adaptor proteins LAT, NTAL, PAG, LIME, TRIM, SIT and LAX organize complex membrane-proximal signalling assemblies and are therefore key mediators of immunoreceptor-mediated signalling. As we discuss here, their identification has greatly facilitated our understanding of how immunoreceptors are connected to intracellular signalling cascades.