Characterization of putative tachykinin peptides in Caenorhabditis elegans

Tachykinin-like peptides, such as substance P, neurokinin A, and B, are among the earliest discovered best-studied neuropeptide families, research on them has contributed greatly to our understanding of endocrine control many physiological processes. However, there still orphan tachykinin receptor homologs for which cognate ligands have not yet been identified, especially in small invertebrates, nematode Caenorhabditis elegans (C. elegans). We here show that C. nlp-58 gene encodes putative G protein-coupled (GPCR) TKR-1, is a worm ortholog receptors. first determine, through an unbiased biochemical screen, peptide derived from NLP-58 preprotein stimulates TKR-1. Three mature peptides predicted be generated potent agonist activity against designate these (CeTK)-1, −2, −3. The CeTK contain C-terminal sequence GLR-amide, shared by tachykinin-like other invertebrate species. exhibits strongly restricted expression pattern several neurons, implying CeTKs behave neuropeptides. discovery provides important information aid their functional interaction with GPCRs.