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J Membr Biol
2012 Aug 01;2458:453-63. doi: 10.1007/s00232-012-9457-z.
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The N-terminal half of the connexin protein contains the core elements of the pore and voltage gates.
Kronengold J, Srinivas M, Verselis VK.
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Connexins form channels with large aqueous pores that mediate fluxes of inorganic ions and biological signaling molecules. Studies aimed at identifying the connexin pore now include a crystal structure that provides details of putative pore-lining residues that need to be verified using independent biophysical approaches. Here we extended our initial cysteine-scanning studies of the TM1/E1 region of Cx46 hemichannels to include TM2 and TM3 transmembrane segments. No evidence of reactivity was observed in either TM2 or TM3 probed with small or large thiol-modifying reagents. Several identified pore residues in E1 of Cx46 have been verified in different Cx isoforms. Use of variety of thiol reagents indicates that the connexin hemichannel pore is large and flexible enough, at least in the extracellular part of the pore funnel, to accommodate uncommonly large side chains. We also find that that gating characteristics are largely determined by the same domains that constitute the pore. These data indicate that biophysical and structural studies are converging towards a view that the N-terminal half of the Cx protein contains the principal components of the pore and gating elements, with NT, TM1 and E1 forming the pore funnel.
Bennett,
Gap junctions: new tools, new answers, new questions.
1991, Pubmed
Bennett,
Gap junctions: new tools, new answers, new questions.
1991,
Pubmed Bukauskas,
Gating properties of gap junction channels assembled from connexin43 and connexin43 fused with green fluorescent protein.
2001,
Pubmed Bukauskas,
Gap junction channel gating.
2004,
Pubmed Duffy,
Formation of the gap junction nexus: binding partners for connexins.
2002,
Pubmed Evans,
The gap junction cellular internet: connexin hemichannels enter the signalling limelight.
2006,
Pubmed Goldberg,
Selective permeability of gap junction channels.
2004,
Pubmed Harris,
Emerging issues of connexin channels: biophysics fills the gap.
2001,
Pubmed Harris,
Kinetic properties of a voltage-dependent junctional conductance.
1981,
Pubmed Hu,
Conductance of connexin hemichannels segregates with the first transmembrane segment.
2006,
Pubmed
,
Xenbase Janecke,
GJB2 mutations in keratitis-ichthyosis-deafness syndrome including its fatal form.
2005,
Pubmed Karlin,
Substituted-cysteine accessibility method.
1998,
Pubmed Kronengold,
Single-channel SCAM identifies pore-lining residues in the first extracellular loop and first transmembrane domains of Cx46 hemichannels.
2003,
Pubmed
,
Xenbase Kronengold,
Pore-lining residues identified by single channel SCAM studies in Cx46 hemichannels.
2003,
Pubmed
,
Xenbase Kwon,
Molecular dynamics simulations of the Cx26 hemichannel: evaluation of structural models with Brownian dynamics.
2011,
Pubmed
,
Xenbase Lee,
Connexin mutations causing skin disease and deafness increase hemichannel activity and cell death when expressed in Xenopus oocytes.
2009,
Pubmed
,
Xenbase Locke,
Post-translational modifications of connexin26 revealed by mass spectrometry.
2009,
Pubmed 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 Neijssen,
Cross-presentation by intercellular peptide transfer through gap junctions.
2005,
Pubmed Oh,
Charges dispersed over the permeation pathway determine the charge selectivity and conductance of a Cx32 chimeric hemichannel.
2008,
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 Ri,
The role of a conserved proline residue in mediating conformational changes associated with voltage gating of Cx32 gap junctions.
1999,
Pubmed
,
Xenbase Sánchez,
Differentially altered Ca2+ regulation and Ca2+ permeability in Cx26 hemichannels formed by the A40V and G45E mutations that cause keratitis ichthyosis deafness syndrome.
2010,
Pubmed
,
Xenbase Skerrett,
Identification of amino acid residues lining the pore of a gap junction channel.
2002,
Pubmed
,
Xenbase Spray,
Equilibrium properties of a voltage-dependent junctional conductance.
1981,
Pubmed
,
Xenbase Srinivas,
Voltage dependence of macroscopic and unitary currents of gap junction channels formed by mouse connexin50 expressed in rat neuroblastoma cells.
1999,
Pubmed Srinivas,
Correlative studies of gating in Cx46 and Cx50 hemichannels and gap junction channels.
2005,
Pubmed
,
Xenbase Tong,
Exchange of gating properties between rat cx46 and chicken cx45.6.
2004,
Pubmed
,
Xenbase Tong,
Structural determinants for the differences in voltage gating of chicken Cx56 and Cx45.6 gap-junctional hemichannels.
2006,
Pubmed
,
Xenbase Trexler,
The first extracellular loop domain is a major determinant of charge selectivity in connexin46 channels.
2000,
Pubmed
,
Xenbase Trexler,
Voltage gating and permeation in a gap junction hemichannel.
1996,
Pubmed
,
Xenbase Valiunas,
Connexin-specific cell-to-cell transfer of short interfering RNA by gap junctions.
2005,
Pubmed Veenstra,
Selectivity of connexin-specific gap junctions does not correlate with channel conductance.
1995,
Pubmed Verselis,
Loop gating of connexin hemichannels involves movement of pore-lining residues in the first extracellular loop domain.
2009,
Pubmed
,
Xenbase Verselis,
Opposite voltage gating polarities of two closely related connexins.
1994,
Pubmed
,
Xenbase Weber,
The permeability of gap junction channels to probes of different size is dependent on connexin composition and permeant-pore affinities.
2004,
Pubmed
,
Xenbase White,
Mouse Cx50, a functional member of the connexin family of gap junction proteins, is the lens fiber protein MP70.
1992,
Pubmed
,
Xenbase Willecke,
Structural and functional diversity of connexin genes in the mouse and human genome.
2002,
Pubmed Zhou,
Identification of a pore lining segment in gap junction hemichannels.
1997,
Pubmed
,
Xenbase
