As the seasons shift and temperatures drop, we feel the cold creeping in. But have you ever wondered exactly how we feel the cold? Scientists have made a groundbreaking discovery, shedding light on the biological mechanisms that allow us to sense cold temperatures. At the heart of this breakthrough is a protein called GluK2, which acts as a tiny sensor in our bodies, enabling us to detect cold conditions.
“We have identified proteins that can detect cool, warm, and hot temperatures,” explains Wenwen Zhang, co-author of the study. “However, little is known about the protein that specifically detects cold temperatures below 15°C.”
This journey into the mysteries of cold sensation began in 2019 with a study on C. elegans, a species of microscopic worms. Scientists found that these worms had a cold-sensitive protein called GluK2, a discovery that sparked interest because this protein also exists in both mice and humans.
To explore its role in mammals, researchers at the University of Michigan conducted experiments by deleting the gene that codes for GluK2 in mice. “We knocked out the GluK2 gene in mice and monitored how they responded to different temperatures. While the mice reacted normally to heat and mechanical stimuli, they showed a clear deficiency in sensing cold, but not cool, temperatures,” Zhang notes.
So, how does GluK2 allow us to feel cold? The research revealed that GluK2 is not just active in the brain – where it was initially thought to assist in transmitting signals between neurons – but also in the peripheral nervous system, the network of nerves located outside the brain and spinal cord. Mice lacking GluK2 in their peripheral nerves were unable to process or respond to cold signals, demonstrating that GluK2 plays a critical role in temperature sensation beyond cognitive function.
What makes this discovery even more fascinating is the potential evolutionary significance of GluK2. The team hypothesised that temperature-sensing might have been the original purpose of this protein, which has ancient relatives dating back to single-celled organisms such as bacteria. Since bacteria do not have brains, they likely used proteins like GluK2 to sense their environment – detecting temperature changes and chemical concentrations. Over time, as life evolved, the function of these proteins expanded and adapted to more complex organisms like humans.
But what does this breakthrough mean for us today? Beyond adding a new piece to the puzzle of how we perceive temperature, this research also offers insight into why some people experience cold differently. For example, cold exposure, especially prolonged exposure, can cause tissue damage and trigger pain – a condition known as cold-induced pain, which currently lacks effective treatments.
“Our studies identify GluK2 as a new drug target for developing therapeutics to treat cold pain,” Zhang explains. This discovery opens the door to new possibilities in managing cold-related health conditions and improving the quality of life for those who suffer from chronic cold sensitivity.
In a world where temperatures can swing dramatically, understanding how our bodies detect and react to the cold can have profound implications – not just for scientific knowledge, but also for developing future medical treatments. This tiny protein, GluK2, could be the key to unlocking relief for those who endure the cold more than others.
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