Natural cytotoxicity triggering receptor 1 is a protein that in humans is encoded by the NCR1 gene. NCR1 has also been designated as CD335 (cluster of differentiation 335). Cytotoxicity-activating receptor that may contribute to the increased efficiency of activated natural killer (NK) cells to mediate tumor cell lysis. Interacts with CD247 and FCER1G. Selectively expressed by both resting and activated NK cells.