(SACRAMENTO, Calif.) -- Scientists have long known the molecular mechanisms behind most of the bodys sensing capabilities. Vision, for example, is made possible in part by rhodopsin, a pigment molecule that is extremely sensitive to light. It is involved in turning photons into electrical signals that can be decoded by the brain into visual information. But how the human body is able to sense a one-degree change in temperature has remained a mystery.
"For a long time, we didnt know how temperature sensing was being carried out in animals," said Jie Zheng, assistant professor in the Department of Physiology and Membrane Biology at the UC Davis School of Medicine. Huge progress was made in the last decade, Zheng said, when scientists discovered four ion channels sensitive to heat and two cold-sensitive ones.
"But, it was still unclear how only six temperature-sensor channels could cover wide ranges of temperature and still discriminate subtle differences," Zheng said.
Using a novel method based on a technique first used by physicists, Zheng and his colleagues now have shown that the subunits of one channel can come together with subunits from another channel or coassemble in laboratory cell cultures to form new functioning channels. Assuming this process also happens in normal cells, it suggests a likely mechanism for the thermosensitivity seen in all animal cells, Zheng explained.
"We found that, by reassembling subunits we potentially have a lot more than six channel types responsible for the sensing of temperature," he said.
The current findings are featured on the cover of the March issue of the Journal of General Physiology and were published online today.
Ion channels are pore-forming proteins found in the membranes of cells. They have the ability to open and close, regulating the flow of charged ions and controlling the voltage gradient found between the inside and outside of every living cell.
Contact: Carole Gan
University of California, Davis - Health System