An Indian-origin researcher has identified that when a temperature-sensing protein within the immune cells trips, it allows the calcium to pour in and activates 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 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.
"Here we show that STIM1 senses temperature and has a profound impact on immune cells," said the study's principal investigator, Scripps Research professor Ardem Patapoutian.
The research team, which included Bertrand Coste and Jayanti Mathur, also of the Patapoutian lab, found that STIM1 could be activated by heat with a high degree of temperature sensitivity.
Both STIM1 and a plasma membrane pore-forming protein known as Orai1 have recently been identified as essential components of the so-called the calcium release activated calcium (CRAC) channel. But STIM1 had not been known to be heat sensitive until this research, according to Xiao.
The study has been detailed in Nature Chemical Biology.