Genetic screening has identified a group of mec (mechanosensory) genes that are required for the function of a set of six touch-receptor neurons in the nematode Caenorhabditis elegans. Such genes potentially encode components of the mechanosensory apparatus. We have cloned one of these genes, mec-10, which is a member of the degenerin gene family (genes such as mec-4 and deg-1 that can be mutated to cause neurodegeneration). Because components of an amiloride-sensitive sodium channel (alpha, beta and gamma rENaC) from rat share considerable sequence similarity with the C. elegans genes, it is likely that degenerins may function as channel proteins. Here we show that two degenerin homologues (mec-4 and mec-10) are expressed in the same cells, although each provides a unique function. Based on genetic data of mutations affecting mec-10-induced degeneration, we propose that the products of three genes (mec-4, mec-10 and mec-6) form a complex needed for mechanosensation, and that several other mec genes may be important in regulating the putative channel complex.