Cold receptor identified

Next time someone gives you the cold shoulder, take some solace in knowing which of your protein receptors detected it. Researchers at the University of California, San Francisco, have identified the principal detector of cold temperatures between about 12 and 26 °C on the basis of work done in mice (Nature, DOI: 10.1038/nature05910). The culprit, called TRPM8, is one member of a family of temperature-sensitive ion channels that can also sense chemical cooling agents such as menthol. TRPM8 or its human version is found in cells all over the mammalian body, including paws (or hands), the spinal cord, and even the cornea. The researchers, led by physiologist David Julius, came to their conclusions by comparing the cold aversion behavior of normal mice with that of mice in which TRPM8 had been knocked out. The mechanism by which TRPM8 senses cold is a "major question that will likely await further insights into the 3-D structure of the ion channel complex," Julius notes.