This gene belongs to a family of genes that function as receptors for tachykinins. Receptor affinities are specified by variations in the 5'-end of the sequence. The receptors belonging to this family are characterized by interactions with G proteins and 7 hydrophobic transmembrane regions. This gene encodes the receptor for the tachykinin neuropeptide substance K, also referred to as neurokinin A.It is associated with G proteins that activate a phosphatidylinositol-calcium second messenger system. It has been reported to be expressed in trachea, lung, and gastrointestinal tract. ESTs have been isolated from human heart/melanocyte/uterus, prostate, and uterus libraries.