Three homologous subunits form a high affinity peptide-gated ion channel in Hydra
Research output: Contribution to journal › Journal article › Research › peer-review
Recently, three ion channel subunits of the degenerin (DEG)/epithelial Na(+) channel (ENaC) gene family have been cloned from the freshwater polyp Hydra magnipapillata, the Hydra Na(+) channels (HyNaCs) 2-4. Two of them, HyNaC2 and HyNaC3, co-assemble to form an ion channel that is gated by the neuropeptides Hydra-RFamides I and II. The HyNaC2/3 channel is so far the only cloned ionotropic receptor from cnidarians and, together with the related ionotropic receptor FMRFamide-activated Na(+) channel (FaNaC) from snails, the only known peptide-gated ionotropic receptor. The HyNaC2/3 channel has pore properties, like a low Na(+) selectivity and a low amiloride affinity, that are different from other channels of the DEG/ENaC gene family, suggesting that a component of the native Hydra channel might still be lacking. Here, we report the cloning of a new ion channel subunit from Hydra, HyNaC5. The new subunit is closely related to HyNaC2 and -3 and co-localizes with HyNaC2 and -3 to the base of the tentacles. Coexpression in Xenopus oocytes of HyNaC5 with HyNaC2 and -3 largely increases current amplitude after peptide stimulation and affinity of the channel to Hydra-RFamides I and II. Moreover, the HyNaC2/3/5 channel has altered pore properties and amiloride affinity, more similarly to other DEG/ENaC channels. Collectively, our results suggest that the three homologous subunits HyNaC2, -3, and -5 form a peptide-gated ion channel in Hydra that could contribute to fast synaptic transmission.
Original language | English |
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Journal | Journal of Biological Chemistry |
Volume | 285 |
Issue number | 16 |
Pages (from-to) | 11958-65 |
Number of pages | 8 |
ISSN | 0021-9258 |
DOIs | |
Publication status | Published - 16 Apr 2010 |
- Amiloride, Amino Acid Sequence, Animals, Cloning, Molecular, Epithelial Sodium Channel, Evolution, Molecular, Feeding Behavior, Female, Hydra, In Situ Hybridization, Ion Channel Gating, Ion Channels, Molecular Sequence Data, Nerve Tissue Proteins, Oocytes, Protein Subunits, Recombinant Proteins, Sequence Homology, Amino Acid, Sodium Channel Blockers, Xenopus laevis
Research areas
ID: 32244979