One more C means no hearing

A miniscule change in a pore protein can mean the difference between hearing and deafness, say Martina Beltramello, Valeria Piazza, Fabio Mammano (Venetian Institute of Molecular Medicine, Padua, Italy), and colleagues. They have characterized a mutant connexin from the inner ear that allows the passage of ions and a dye, but not of the intracellular messenger inositol 1,4,5-trisphosphate (IP₃). The result is a failure in hearing.The connexin is expressed in supporting cells in the organ of Corti (http://www.vimm.it/cochlea). These cells are thought to ferry K⁺ away from sensory cells, thus preventing opening of channels in these cells that would admit toxic levels of Ca²⁺.

Most connexin mutations associated with deafness yield missorted or nonfunctional channel proteins. The Italian group focused on...