Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Localization of a voltage gate in connexin46 gap junction hemichannels.
Pfahnl A, Dahl G.
???displayArticle.abstract???
Cysteine replacement mutagenesis has identified positions in the first transmembrane domain of connexins as contributors to the pore lining of gap junction hemichannels (Zhou et al. 1997. Biophys. J. 72:1946-1953). Oocytes expressing a mutant cx46 with a cysteine in position 35 exhibited a membrane conductance sensitive to the thiol reagent maleimidobutyryl biocytin (MBB). MBB irreversibly reduced the single-channel conductance by 80%. This reactive cysteine was used to probe the localization of a voltage gate that closes cx46 gap junction hemichannels at negative potentials. MBB was applied to the closed channel either from outside (whole cell) or from inside (excised membrane patches). After washout of the thiol reagent the channels were tested at potentials at which the channels open. After extracellular application of MBB to intact oocytes, the membrane conductance was unaffected. In contrast, channels treated with intracellular MBB were blocked. Thus the cysteine in position 35 of cx46 is accessible from inside but not from the outside while the channel is closed. These results suggest that the voltage gate, which may be identical to the "loop gate" (Trexler et al. 1996. Proc. Natl. Acad. Sci. USA. 93:5836-5841), is located extracellular to the 35 position. The voltage gate results in regional closure of the pore rather than closure along the entire pore length.
Armstrong,
Interaction of tetraethylammonium ion derivatives with the potassium channels of giant axons.
1971, Pubmed
Armstrong,
Interaction of tetraethylammonium ion derivatives with the potassium channels of giant axons.
1971,
Pubmed Barrio,
Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage.
1991,
Pubmed
,
Xenbase Baud,
Sodium channels induced by depolarization of the Xenopus laevis oocyte.
1982,
Pubmed
,
Xenbase Bennett,
Gap junctions: new tools, new answers, new questions.
1991,
Pubmed Beyer,
Connexin family of gap junction proteins.
1990,
Pubmed Bukauskas,
Heterotypic gap junction channels (connexin26-connexin32) violate the paradigm of unitary conductance.
1995,
Pubmed Ebihara,
Properties of a nonjunctional current expressed from a rat connexin46 cDNA in Xenopus oocytes.
1993,
Pubmed
,
Xenbase Ebihara,
Distinct behavior of connexin56 and connexin46 gap junctional channels can be predicted from the behavior of their hemi-gap-junctional channels.
1995,
Pubmed
,
Xenbase Ek-Vitorín,
PH regulation of connexin43: molecular analysis of the gating particle.
1996,
Pubmed
,
Xenbase Gupta,
Bovine connexin44, a lens gap junction protein: molecular cloning, immunologic characterization, and functional expression.
1994,
Pubmed
,
Xenbase Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed Holmgren,
Trapping of organic blockers by closing of voltage-dependent K+ channels: evidence for a trap door mechanism of activation gating.
1997,
Pubmed Hoshi,
Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
1990,
Pubmed
,
Xenbase Kelsell,
Connexin 26 mutations in hereditary non-syndromic sensorineural deafness.
1997,
Pubmed Liu,
Gated access to the pore of a voltage-dependent K+ channel.
1997,
Pubmed Loewenstein,
Junctional intercellular communication: the cell-to-cell membrane channel.
1981,
Pubmed Oh,
Changes in permeability caused by connexin 32 mutations underlie X-linked Charcot-Marie-Tooth disease.
1997,
Pubmed
,
Xenbase Paul,
Connexin46, a novel lens gap junction protein, induces voltage-gated currents in nonjunctional plasma membrane of Xenopus oocytes.
1991,
Pubmed
,
Xenbase Pfahnl,
A chimeric connexin forming gap junction hemichannels.
1997,
Pubmed
,
Xenbase Rubin,
Molecular analysis of voltage dependence of heterotypic gap junctions formed by connexins 26 and 32.
1992,
Pubmed
,
Xenbase Tan,
Novel mutations in the connexin 32 gene associated with X-linked Charcot-Marie tooth disease.
1996,
Pubmed Trexler,
Voltage gating and permeation in a gap junction hemichannel.
1996,
Pubmed
,
Xenbase Unwin,
The structure of ion channels in membranes of excitable cells.
1989,
Pubmed Unwin,
Structure of the junction between communicating cells.
1980,
Pubmed Unwin,
Two configurations of a channel-forming membrane protein.
,
Pubmed Veenstra,
Size and selectivity of gap junction channels formed from different connexins.
1996,
Pubmed Verselis,
Opposite voltage gating polarities of two closely related connexins.
1994,
Pubmed
,
Xenbase Werner,
Formation of hybrid cell-cell channels.
1989,
Pubmed
,
Xenbase White,
Voltage gating of connexins.
1994,
Pubmed
,
Xenbase Wilders,
Limitations of the dual voltage clamp method in assaying conductance and kinetics of gap junction channels.
1992,
Pubmed Zhou,
Identification of a pore lining segment in gap junction hemichannels.
1997,
Pubmed
,
Xenbase
