PUBLICATION
Species-specific voltage-gating properties of connexin-45 junctions expressed in Xenopus oocytes
- Authors
- Barrio, L.C., Capel, J., Jarillo, J.A., Castro, C., and Revilla, A.
- ID
- ZDB-PUB-971203-14
- Date
- 1997
- Source
- Biophysical journal 73(2): 757-769 (Journal)
- Registered Authors
- Keywords
- none
- MeSH Terms
-
- Mice
- Zebrafish
- Models, Structural
- Chickens
- Humans
- Oocytes/physiology
- Protein Structure, Secondary
- Xenopus laevis
- Gap Junctions/physiology*
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Connexins/biosynthesis
- Connexins/chemistry
- Connexins/physiology*
- Species Specificity
- Kinetics
- Membrane Potentials
- Animals
- Female
- Ion Channel Gating
- PubMed
- 9251792 Full text @ Biophys. J.
Citation
Barrio, L.C., Capel, J., Jarillo, J.A., Castro, C., and Revilla, A. (1997) Species-specific voltage-gating properties of connexin-45 junctions expressed in Xenopus oocytes. Biophysical journal. 73(2):757-769.
Abstract
Gap junctions composed of connexin-45 (Cx45) homologs from four species, zebrafish, chicken, mouse, and human, were expressed in pairs of Xenopus oocytes. The macroscopic conductance (gj) of all Cx45 junctions was modulated by transjunctional voltage (Vj) and by the inside-outside voltage (Vm), and the modulation was species specific. Although their gating characteristics varied in voltage sensitivity and kinetics, the four Cx45 junctions shared 1) maximum conductance at Vj = 0 and symmetrical gj reduction in response to positive and negative Vj of low amplitude, with little residual conductance; and 2) gj increases in response to simultaneous depolarization of the paired cells. The formation of hybrid channels, comprising Cx45 hemichannels from different species, allowed us to infer that two separate gates exist, one in each hemichannel, and that each Cx45 hemichannel is closed by the negativity of Vj on its cytoplasmic side. Interestingly, the Vm dependence of hybrid channels also suggests the presence of two gates in series, one Vm gate in each hemichannel. Thus the Vj and Vm dependence provides evidence that two independent voltage gates in each Cx45 hemichannel exist, reacting through specific voltage sensors and operating by different mechanisms, properties that have evolved divergently among species.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping