A STOMATIN-LIKE PROTEIN NECESSARY FOR MECHANOSENSATION IN C-ELEGANS

The mec-2 gene is required for the function of a set of six touch rece ptor neurons in the nematode Caenorhabditis elegans; mec-2 mutants, wh ich are touch-insensitive, have touch cells that appear morphologicall y normal(1,2). Gene interaction studies suggest that mec-2 positively regulates the activity of the putative mechanosensory transduction cha nnel (ref. 3 and the present paper), comprised in part of proteins enc oded by the two degenerin genes mec-4 and mec-10 (refs 3-5). The centr al region of the mec-2 protein (MEC-2) is very similar to stomatin, an integral membrane protein (band 7.2b) in human red blood cells that i s thought to regulate cation conductance(6). MEC-2-LacZ fusions are di stributed along the touch receptor axons. This axonal distribution, wh ich is mediated by the mec-2-specific amino terminus, is disrupted by mutations in mec-12, an alpha-tubulin gene needed for touch cell funct ion. Our results indicate that MEC-2 links the mechanosensory channel and the microtubule cytoskeleton of the touch receptor neurons. Such l inkage provides the basis for a mechanism of mechanosensation whereby microtubule displacement leads to channel opening.