NKG2D/DAP10 Signaling recruits EVL to the cytotoxic synapse to generate F-actin and promote NK cell cytotoxicity

Abstract

Natural killer (NK) cells eliminate abnormal cells through the release of cytolytic granule contents. In this process, NK cells must adhere to target cells through integrin-mediated adhesion, which is highly dependent on the generation of F-actin. Ena/VASP-like (EVL) is an actin regulatory protein previously shown to regulate integrin-mediated adhesion in other cell types, but its role in NK cell biology is not known. Herein, we show that EVL is recruited to the NK cell cytotoxic synapse and is required for NK cell cytotoxicity. Significantly, EVL is involved in the generation of F-actin at the cytotoxic synapse, antibody-stimulated spreading, and NK cell-target cell adhesion. EVL interacts with WASP and VASP and is required for localization of both proteins to the synapse. Recruitment of EVL to points of cellular activation occurs in a DAP10-dependent manner, through a binding site previously implicated in VAV1/Grb2 recruitment. In all, this study implicates DAP10-mediated Grb2/VAV1 signaling in the recruitment of an EVL-containing actin regulatory complex to the cytotoxic synapse where it can promote F-actin nucleation leading to NK cell-mediated killing.