Caenorhabditis elegans Sre proteins are candidate chemosensory receptors. There are four main recognised groups of such receptors: Odr-10, Sra, Sro, and Srg. Sre (this family), Sra Pfam:PF02117 and Srb Pfam:PF02175 comprise the Sra group. All of the above receptors are thought to be G protein-coupled seven transmembrane domain proteins [1,2]. The existence of several different chemosensory receptors underlies the fact that in spite of having only 20-30 chemosensory neurones, C. elegans detects hundreds of different chemicals, with the ability to discern individual chemicals among combinations [1].

1: Chemosensory signaling in C. elegans. Troemel ER; Bioessays 1999;21:1011-1020. PMID:10580986

2: Divergent seven transmembrane receptors are candidate chemosensory receptors in C. elegans. Troemel ER, Chou JH, Dwyer ND, Colbert HA, Bargmann CI; Cell 1995;83:207-218. PMID:7585938