An Odor Like No Other: Unique Proteins Involved in Smell Recognition

Background: The sense of smell is necessary for mammals to communicate with their environment. The sensory nerve receptors of the vomeronasal organ (VNO) in the nose plays an essential role in the detection of chemical signals secreted by mammals that influence gender, reproductive status, and social dominance. It has been difficult for scientists to define the molecular nature of such signals. One possibility is proteins of the major histocompatibility complex (MHC) class I molecules. MHC molecules play an important role in defining an individual’s tissue type by providing a specific cellular marker that is unique for each individual.

Advance: NIDCD-supported scientists have discovered that peptides derived from MHC proteins could provide a special signal that exerts its action via the activation of sensory receptor neurons of the vomeronasal system. When MHC peptides are not kept on cell surfaces and are released in bodily secretions, they represent a previously unknown family of chemosensory stimuli that can influence social behavior and individuality within a species.

Implications: Pheromones serve as hormones that communicate fundamentally different information and activate the olfactory system in a different way than the smell of food or other airborne compounds. Pheromones convey a variety of socially relevant cues, ranging from the mating status of a female to secretions released during territorial scent marking. These findings demonstrate that MHC peptides activate receptors of the VMO and function as a chemosensory signal, which provides additional information about the genetic status of an individual and allows an animal to uniquely identify another animal as friend or foe.

Citation: Leinders-Zufall T, Brennan P, Widmayer P, Chandramani P, Maul-Pavicic A, Jager M, Li XH, Breer H, Zufall F, Boehm T, MHC Class I Peptides as Chemosensory Signals in the Vomeronasal Organ Science 306: 1033-1037, 2004.

Link to publication: http://www.sciencemag.org/cgi/content/full/306/5698/1033

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