1. Identification of multiple urechistachykinin peptides, gene expression, pharmacological activity, and detection using mass spectrometric analyses
Y Muneoka, K Nomoto, T Kawada, H Satake, H Minakata, K Masuda Peptides . 2000 Dec;21(12):1777-83. doi: 10.1016/s0196-9781(00)00338-7.
Urechistachykinin I and II (Uru-TK I and II) are invertebrate tachykinin-related peptides (TRPs), which have been isolated from echiuroid worms. The cDNA sequence encoding the Uru-TK I and II revealed that the precursor also encoded five TRP-like peptides. Here, we report the characterization of these Uru-TK-like peptides named as Uru-TK III-VII. Northern and Southern blot analyses demonstrated that Uru-TK mRNA is localized in nerve tissue. In addition, the presence of the Uru-TK-like peptides as matured forms in the nerve tissue was detected by mass spectrometric analysis, and identified these peptides were shown to exhibit a contractile activity on cockroach hindgut that was as potent as that of Uru-TK II. Furthermore, synthetic Uru-TK-like peptide analogs which contained Met-NH2 instead of Arg-NH2 at their C-termini were shown to possess a potential to bind to a mammalian tachykinin receptor, indicating that Uru-TK-like peptides are likely to correspond to vertebrate tachykinins, except for the difference at the C-terminal residue. These findings show that Uru-TK-like peptides are essentially equivalent to Uru-TK I and II, leading to the proposal that Uru-TK-like peptides play an essential role as invertebrate tachykinin neuropeptides.
2. Antimicrobial effect and membrane-active mechanism of Urechistachykinins, neuropeptides derived from Urechis unicinctus
So Hyun Park, Dong Gun Lee, Woo Sang Sung FEBS Lett . 2008 Jul 9;582(16):2463-6. doi: 10.1016/j.febslet.2008.06.015.
We investigated the antimicrobial effects of Urechistachykinins I and II (UI and UII) and their modes of action. UI and UII showed antimicrobial activities without a hemolytic effect. To investigate the mechanism(s) of UI and UII, cellular localization was examined. Confocal microscopy results showed that peptides were located in the cell envelope. To elucidate the physical changes of membrane induced by UI and UII in Candida albicans, flow cytometry analyses were performed by using bis-(1,3-dibutylbarbituric acid) trimethine oxonol, and changes in membrane dynamics were assessed using 1,6-diphenyl-1,3,5-hexatriene. The results suggest that UI and UII may exert their antimicrobial effect by disrupting the cell membranes.
3. Actions of tachykinins on the ion transport across the frog skin
C Lippe, S Lobasso, C Ardizzone, V Bellantuono, G Cassano Peptides . 1998;19(8):1435-8. doi: 10.1016/s0196-9781(98)00080-1.
The tachykinin-dependent stimulation of ion transport across frog skin was studied. Tachykinin stimulation was due to interaction with an NK1-like receptor as [Sar9-Met(O2)11]-Substance P (a very selective NK1 agonist) strongly stimulated SCC, whereas [beta-Ala8]-Neurokinin A 4-10 (a very selective NK2 agonist) did not. The rank order of tachykinin potency was: PG-KI > Uperolein > Hylambatin > Kassinin > Phyllomedusin > [Sar9-Met(O2)11]-Substance P > Ranatachykinin A > Physalaemin > Ranakinin > Substance P and Eledoisin >> Neurokinin A. Neurokinin B, Scyliorhinin I, Urechistachykinin I and Urechistachykinin II had no effect. We conclude that the minimal structural requirements for stimulating SCC in the frog skin were the presence of: a) the C-terminal sequence Phe-X-Gly-Leu-Met-NH2; b) at least one Pro residue in the N-terminal sequence.
