In an article that will appear in this week's issue of the journal Cell, the group describes the "ion channel" protein, called ANKTM1, which is the first noxious (painful) cold receptor identified, and may be an important basic target for pain-modulating drugs.
Despite the fact that researchers at several other laboratories had previously identified receptors that sense hot temperatures, warm temperatures, and cool temperatures, the protein that detects cold temperatures had been conspicuously absent. "This was one of the remaining puzzles," says TSRI Assistant Professor of Cell Biology Ardem Patapoutian, who led the effort with TSRI Research Associate Gina Story.
The cold receptor protein ANKTM1 was overlooked, note Patapoutian and Story, because it is distantly related to the hot, warm, and cool receptors. As such, ANKTM1 has very low sequence homology, or DNA similarity, with these other proteins.
But when they studied it in the laboratory, Patatpoutian and Story found that even though ANKTM1 did not "look" like a temperature receptor, it sure acted like one. "We found that if we applied very cold stimuli, the channel would open in response," says Story.
Hot, Cold, and Everything In Between
Humans and other vertebrate animals use specialized sensory neurons to detect temperature, pressure, and other physical stimuli on the skin. These neurons are located in the spinal column and are connected to the skin and organs through long extensions known as axons.
On the surface of these axons are the protein channel molecules, like ANKTM1 and its cousins the hot, warm, and cool receptors, which span the axon's membrane, connecting the inside with the outside. These r
Contact: Jason Bardi
Scripps Research Institute