Thought to form a receptor-activated non-selective calcium permeant cation channel. Probably is operated by a phosphatidylinositol second messenger system activated by receptor tyrosine kinases or G-protein coupled receptors. May also be activated by intracellular calcium store depletion. Plays a role in mediating responsivity to pheromones that elicit aggressive and mating behaviors. Required for response to the Esp1 pheromone which enhances female sexual receptive behavior and to the Esp22 pheromone which inhibits adult male mating behavior. Isoform 3 is ubiquitously expressed at low levels. Isoform 4 is expressed exclusively in vomeronasal organ. Reduced electrophysiological response to pheromone mixtures in the vomeronasal organ. Mutant males and nursing females are docile and fail to initiate aggressive attacks on intruder males. Males display normal mating behavior towards females but display increased sexual behavior towards prepubescent females even when presented simultaneously with adult estrus females and also show increased sexual behavior towards juvenile and adult males. Lack of response to Esp1. Belongs to the transient receptor (TC 1.A.4) family. STrpC subfamily. TRPC2 sub-subfamily.