Assembling atomic resolution views of the immunological synapse

Antigen-dependent T-cell activation is initiated by the organized interactions of a host of cell-surface receptors in the interface between the T cell and an antigen-presenting cell. Recent structural studies of many of the receptors that comprise this ‘immunological synapse’, including integrins, cadherins and co-stimulatory molecules, reveal in detail the molecular interactions that bridge the synapse. Additionally, structural analyses of the cytoplasmic tails of integrins and co-stimulatory receptors in complex with intracellular signaling proteins are providing insight into the mechanisms that couple receptor clustering on the cell surface with the initiation of cytoplasmic signaling.