Nematode chemoreceptor


Nematode chemoreceptors are chemoreceptors of nematodes.
Animals recognise a wide variety of chemicals using their senses of taste and smell. The nematode Caenorhabditis elegans has only 14 types of chemosensory neuron, yet is able to respond to dozens of chemicals because each neuron detects several stimuli. More than 40 highly divergent transmembrane proteins that could contribute to this functional diversity have been described. Most of the candidate receptor genes are in clusters of similar genes; 11 of these appear to be expressed in small subsets of chemosensory neurons. A single type of neuron can potentially express at least 4 different receptor genes. Some of these might encode receptors for water-soluble attractants, repellents and pheromones, which are divergent members of the G-protein-coupled receptor family. Sequences of the Sra family of C. elegans receptor-like proteins contain 6-7 hydrophobic, putative transmembrane, regions. These can be distinguished from other 7TM proteins by their own characteristic TM signatures.
More than 1300 potential chemoreceptor genes have been identified in C. elegans, which are generally prefixed sr for receptor. The receptor superfamilies include Sra, Str and Srg, as well as the families Srw, Srz, Srbc, Srsx and Srr. Many of these proteins have homologues in Caenorhabditis briggsae.
These receptors are distantly related to the Rhodopsin-like receptors.