Researchers at The Scripps Research Institute and the Novartis Research Foundation have found a temperature-sensing protein within immune cells that, when tripped, allows calcium to pour in and activate an immune response. This process can occur as temperature rises, such as during a fever, or when it falls—such as when immune cells are "called" from the body's warm interior to a site of injury on cooler skin. The study, published online on April 17, 2011 in Nature Chemical Biology, is the first to find such a sensor in immune cells—specifically, in the T lymphocytes that play a central role in activation of killer immune cells. The protein, STIM1, previously known as an endoplasmic reticulum (ER) calcium sensor, had been thought to be important in immune function, and now the scientists show it is also a temperature sensor. "Temperature has a profound effect on all biological processes including immune responses, but surprisingly little is known about molecules in immune cells that sense temperature shifts," said the study's principal investigator, Scripps Research Professor Ardem Patapoutian. "Here we show that STIM1 senses temperature and has a profound impact on immune cells." This is the second family of thermosensation molecules that the Patapoutian laboratory has uncovered. The team has isolated and characterized three of six members of the transient receptor potential (TRP) family of ion channels—the so-called thermoTRPs. "These proteins translate temperature, which is a physical stimulus, into a chemical signal—ions flowing into cells," said Dr. Patapoutian. "ThermoTRPs mainly function in specialized sensory neurons that relay environmental temperature information to the brain." In this study, the researchers turned to immune cells to look for temperature sensors.Login Or Register To Read Full Story