Protein Senses High Levels Of Salt

The transmembrane channel-like family of proteins has been a mystery to scientists. Researchers have known that mutations in one member, called TMC-1, have been linked to human deafness. But they haven’t learned much about the proteins’ structure or function. A team led by Sun Wook Hwang of Korea University College of Medicine and William R. Schafer of the MRC Laboratory of Molecular Biology, in England, has now shown that a TMC protein is necessary for sensing an outside stimulus (Nature, DOI: 10.1038/nature11845). Using genetic engineering and fluorescence imaging methods, the researchers found that in the nematode Caenorhabditis elegans TMC-1 is responsible for perceiving harmful quantities of salt. They think TMC-1 forms either an ion channel itself or part of a channel that gets triggered by sodium ions in the worms’ surroundings. The results, Schafer says, “suggest that other TMCs may form or contribute to ion channels involved in sensory transduction.” Studies are under way, he adds, to learn about human TMC proteins by inserting them into worm nerve cells.