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A novel tachykinin‐related peptide receptor of Octopus vulgaris – evolutionary aspects of invertebrate tachykinin and tachykinin‐related peptide
Author(s) -
Kanda Atsuhiro,
TakuwaKuroda Kyoko,
Aoyama Masato,
Satake Honoo
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05760.x
Subject(s) - tachykinin receptor , biology , receptor , subfamily , octopus (software) , g protein coupled receptor , peptide , xenopus , microbiology and biotechnology , neuropeptide , biochemistry , substance p , gene , chemistry , computational chemistry
The tachykinin (TK) and tachykinin‐related peptide (TKRP) family represent one of the largest peptide families in the animal kingdom and exert their actions via a subfamily of structurally related G‐protein‐coupled receptors. In this study, we have identified a novel TKRP receptor from the Octopu s heart, oct‐TKRPR. oct‐TKRPR includes domains and motifs typical of G‐protein‐coupled receptors. Xenopus oocytes that expressed oct‐TKRPR, like TK and TKRP receptors, elicited an induction of membrane chloride currents coupled to the inositol phosphate/calcium pathway in response to Octopus TKRPs (oct‐TKRP I–VII) with moderate ligand selectivity. Substance P and Octopus salivary gland‐specific TK, oct‐TK‐I, completely failed to activate oct‐TKRPR, whereas a Substance P analog containing a C‐terminal Arg‐NH 2 exhibited equipotent activation of oct‐TKRPs. These functional analyses prove that oct‐TKRPs, but not oct‐TK‐I, serve as endogenous functional ligands through oct‐TKRPR, although both of the family peptides were identified in a single species, and the importance of C‐terminal Arg‐NH 2 in the specific recognition of TKRPs by TKRPR is conserved through evolutionary lineages of Octopus . Southern blotting of RT‐PCR products revealed that the oct‐TKRPR mRNA was widely distributed in the central and peripheral nervous systems plus several peripheral tissues. These results suggest multiple physiologic functions of oct‐TKRPs as neuropeptides both in the Octopus central nervous system and in peripheral tissues. This is the first report on functional discrimination between invertebrate TKRPs and salivary gland‐specific TKs.