Natural killer (NK) cells kill virally infected and tumorigenic cells. They do this by forming a highly organized, actin-dependent lytic immunological synapse with their target. We imaged F-actin in an NK cell forming a lytic synapse by 3D STED super-resolution microscopy. Images were acquired on a Leica SP5 with time-gated STED and then deconvolved and rendered with Huygens software. Print all four for the complete synapse!