V1R

V1R, short for vomeronasal receptor type-1, refers to a family of G protein-coupled receptors expressed in the vomeronasal organ of many vertebrates. These receptors participate in the detection of pheromone-like chemical cues and play a role in mediating social and reproductive behaviors.

The V1R gene family comprises numerous paralogs, each encoding a receptor that localizes to vomeronasal sensory neurons, typically in the apical layer. Upon ligand binding, V1R receptors can couple to G proteins such as G_q/11, triggering intracellular signaling that conveys information to the accessory olfactory bulb and, from there, to higher brain regions involved in behavior.

Distribution and evolution of V1R genes show rapid pairwise evolution and lineage-specific repertoires. This birth-and-death dynamic leads to substantial variation between species in the number and function of V1R genes. In some lineages, many V1R genes have become pseudogenes. In humans, the vomeronasal organ is largely vestigial, and functional V1R genes are largely absent, suggesting a diminished role for V1R-mediated pheromone detection in our species.

Ligands for many V1Rs remain largely unknown, and many receptors are still considered orphan. Research approaches include gene knockout models, expression assays, and behavioral experiments to link specific V1R activation to social cues such as mating, kin recognition, and aggression. V1Rs are distinct from the related V2R family, which typically detects different classes of chemical signals within the vomeronasal system.