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Connexin hemichannels display two distinct forms of voltage-dependent gating, corresponding to the operation of Vj- or fast gates and loop- or slow gates. The carboxyl terminus (CT) of connexin 32 has been reported to be required for the operation of the Vj (fast) gates, but this conclusion was inferred from the loss of a fast kinetic component in macroscopic currents of CT-truncated intercellular channels elicited by transjunctional voltage. Such inferences are complicated by presence of both fast and slow gates in each hemichannel and the serial head-to-head arrangement of these gates in the intercellular channel. Examination of voltage gating in undocked hemichannels and Vj gate polarity reversal by a negative charge substitution (N2E) in the amino terminal domain allow unequivocal separation of the two gating processes in a Cx32 chimera (Cx32(∗)43E1). This chimera expresses currents as an undocked hemichannel in Xenopus oocytes and provides a model system to study the molecular determinants and mechanisms of Cx32 voltage gating. Here, we demonstrate that both Vj- and loop gates are operational in a truncation mutation that removes all but the first four CT residues (ACAR(219)) of the Cx32(∗)43E1 hemichannel. We conclude that an operational Cx32 Vj (fast) gate does not require CT residues 220-283, as reported previously by others.
Bargiello,
Voltage-dependent conformational changes in connexin channels.
2012, Pubmed,
Xenbase
Bargiello,
Voltage-dependent conformational changes in connexin channels.
2012,
Pubmed
,
Xenbase
Barrio,
Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage.
1991,
Pubmed
,
Xenbase
Bouvier,
Characterization of the structure and intermolecular interactions between the connexin40 and connexin43 carboxyl-terminal and cytoplasmic loop domains.
2009,
Pubmed
,
Xenbase
Bukauskas,
Gap junction channel gating.
2004,
Pubmed
Contreras,
Gating and regulation of connexin 43 (Cx43) hemichannels.
2003,
Pubmed
Ebihara,
Xenopus connexin38 forms hemi-gap-junctional channels in the nonjunctional plasma membrane of Xenopus oocytes.
1996,
Pubmed
,
Xenbase
Egwolf,
Ion selectivity of alpha-hemolysin with beta-cyclodextrin adapter. II. Multi-ion effects studied with grand canonical Monte Carlo/Brownian dynamics simulations.
2010,
Pubmed
González,
Molecular basis of voltage dependence of connexin channels: an integrative appraisal.
2007,
Pubmed
González,
Species specificity of mammalian connexin-26 to form open voltage-gated hemichannels.
2006,
Pubmed
,
Xenbase
Hirst-Jensen,
Characterization of the pH-dependent interaction between the gap junction protein connexin43 carboxyl terminus and cytoplasmic loop domains.
2007,
Pubmed
Im,
A Grand Canonical Monte Carlo-Brownian dynamics algorithm for simulating ion channels.
2000,
Pubmed
Kwon,
Molecular dynamics simulations of the Cx26 hemichannel: evaluation of structural models with Brownian dynamics.
2011,
Pubmed
,
Xenbase
Lopez,
Insights on the mechanisms of Ca(2+) regulation of connexin26 hemichannels revealed by human pathogenic mutations (D50N/Y).
2013,
Pubmed
,
Xenbase
Maeda,
Structure of the connexin 26 gap junction channel at 3.5 A resolution.
2009,
Pubmed
Moreno,
Role of the carboxyl terminal of connexin43 in transjunctional fast voltage gating.
2002,
Pubmed
,
Xenbase
Oh,
Stoichiometry of transjunctional voltage-gating polarity reversal by a negative charge substitution in the amino terminus of a connexin32 chimera.
2000,
Pubmed
,
Xenbase
Oh,
Determinants of gating polarity of a connexin 32 hemichannel.
2004,
Pubmed
,
Xenbase
Oh,
Molecular determinants of electrical rectification of single channel conductance in gap junctions formed by connexins 26 and 32.
1999,
Pubmed
Oshima,
Three-dimensional structure of a human connexin26 gap junction channel reveals a plug in the vestibule.
2007,
Pubmed
Puljung,
Polyvalent cations constitute the voltage gating particle in human connexin37 hemichannels.
2004,
Pubmed
,
Xenbase
Purnick,
Reversal of the gating polarity of gap junctions by negative charge substitutions in the N-terminus of connexin 32.
2000,
Pubmed
,
Xenbase
Rackauskas,
Gating properties of heterotypic gap junction channels formed of connexins 40, 43, and 45.
2007,
Pubmed
Revilla,
Molecular dissection of transjunctional voltage dependence in the connexin-32 and connexin-43 junctions.
1999,
Pubmed
,
Xenbase
Rubin,
Molecular analysis of voltage dependence of heterotypic gap junctions formed by connexins 26 and 32.
1992,
Pubmed
,
Xenbase
Seki,
Modifications in the biophysical properties of connexin43 channels by a peptide of the cytoplasmic loop region.
2004,
Pubmed
Shibayama,
Identification of a novel peptide that interferes with the chemical regulation of connexin43.
2006,
Pubmed
Shibayama,
Effect of charge substitutions at residue his-142 on voltage gating of connexin43 channels.
2006,
Pubmed
,
Xenbase
Srinivas,
Correlative studies of gating in Cx46 and Cx50 hemichannels and gap junction channels.
2005,
Pubmed
,
Xenbase
Stauch,
Characterization of the structure and intermolecular interactions between the connexin 32 carboxyl-terminal domain and the protein partners synapse-associated protein 97 and calmodulin.
2012,
Pubmed
Tang,
Conformational changes in a pore-forming region underlie voltage-dependent "loop gating" of an unapposed connexin hemichannel.
2009,
Pubmed
,
Xenbase
Trexler,
Voltage gating and permeation in a gap junction hemichannel.
1996,
Pubmed
,
Xenbase
Trexler,
Rapid and direct effects of pH on connexins revealed by the connexin46 hemichannel preparation.
1999,
Pubmed
,
Xenbase
Verselis,
Divalent cations regulate connexin hemichannels by modulating intrinsic voltage-dependent gating.
2008,
Pubmed
,
Xenbase
Verselis,
Opposite voltage gating polarities of two closely related connexins.
1994,
Pubmed
,
Xenbase
