The killer's kiss: the many functions of NK cell immunological synapses.

Natural killer (NK) cells comprise a subset of lymphocytes involved in protection against microbial pathogens and tumors. NK cells recognize host cells that are missing MHC class I molecules and eliminate them through localized delivery of lytic granules. The majority of NK cell effector functions require direct cell-to-cell contact. Binding to a target cell is accompanied by creation of complex structures at the cell-cell interface known as immunological synapses. Recent studies have contributed immensely to the characterization of several types of NK cell immunological synapses and understanding of the variety of processes originating at this intriguing place. The emerging picture illustrates NK cell immune synapses as the sites of highly complex regulation of NK cell activity.