TY - JOUR
T1 - Three homologous subunits form a high affinity peptide-gated ion channel in Hydra
AU - Dürrnagel, Stefan
AU - Kuhn, Anne
AU - Tsiairis, Charisios D
AU - Williamson, Michael
AU - Kalbacher, Hubert
AU - Grimmelikhuijzen, Cornelis J P
AU - Holstein, Thomas W
AU - Gründer, Stefan
PY - 2010/4/16
Y1 - 2010/4/16
N2 - 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.
AB - 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.
KW - Amiloride
KW - Amino Acid Sequence
KW - Animals
KW - Cloning, Molecular
KW - Epithelial Sodium Channel
KW - Evolution, Molecular
KW - Feeding Behavior
KW - Female
KW - Hydra
KW - In Situ Hybridization
KW - Ion Channel Gating
KW - Ion Channels
KW - Molecular Sequence Data
KW - Nerve Tissue Proteins
KW - Oocytes
KW - Protein Subunits
KW - Recombinant Proteins
KW - Sequence Homology, Amino Acid
KW - Sodium Channel Blockers
KW - Xenopus laevis
U2 - 10.1074/jbc.M109.059998
DO - 10.1074/jbc.M109.059998
M3 - Journal article
C2 - 20159980
SN - 0021-9258
VL - 285
SP - 11958
EP - 11965
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 16
ER -