For decades, biologists have been trying to find the crucial sensor protein in nerve endings that translates muscle and tendon stretching into proprioceptive nerve signals.
Now in a study published in Nature Neuroscience on November 9, 2015, a team led by scientists from The Scripps Research Institute has identified this sensor protein in mice.
“To the layman it might not seem surprising that touch and proprioception would use the same sensor protein, but within this field there has been a lot of evidence suggesting otherwise-so finding that Piezo2 does both was a surprise,” said lead investigator Ardem Patapoutian, a professor at TSRI and investigator with Howard Hughes Medical Institute.
In two studies published last year, they identified Piezo2 as the principal sensor for ordinary, non-painful touch in mice. Prior studies had suggested that the main stretch-sensing protein expressed by proprioceptive neurons is one that specializes in admitting sodium ions.
The team found evidence from these initial tests that the main ion-channel protein on proprioceptive neurons is not a selective sodium-channel protein, but in fact has properties consistent with Piezo2s.
Explore further: Scientists identify principal protein sensor for touch.