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Reversal of the gating polarity of gap junctions by negative charge substitutions in the N-terminus of connexin 32.
Purnick PE
,
Oh S
,
Abrams CK
,
Verselis VK
,
Bargiello TA
.
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Intercellular channels formed by connexins (gap junctions) are sensitive to the application of transjunctional voltage (V(j)), to which they gate by the separate actions of their serially arranged hemichannels (Harris, A. L., D. C. Spray, and M. V. L. Bennett. 1981. J. Gen. Physiol. 77:95-117). Single channel studies of both intercellular and conductive hemichannels have demonstrated the existence of two separate gating mechanisms, termed "V(j)-gating" and "loop gating" (Trexler, E. B., M. V. L. Bennett, T. A. Bargiello, and V. K. Verselis. 1996. Proc. Natl. Acad. Sci. U.S.A. 93:5836-5841). In Cx32 hemichannels, V(j)-gating occurs at negative V(j) (Oh, S., J. B. Rubin, M. V. L. Bennett, V. K. Verselis, and T. A. Bargiello. 1999. J. Gen. Physiol. 114:339-364; Oh, S., C. K. Abrams, V. K. Verselis, and T. A. Bargiello. 2000. J. Gen. Physiol. 116:13-31). A negative charge substitution at the second amino acid position in the N-terminus reverses the polarity of V(j)-gating of Cx32 hemichannels (Verselis, V. K., C. S. Ginter, and T. A. Bargiello. 1994. Nature. 368:348-351;. J. Gen. Physiol. 116:13-31). We report that placement of a negative charge at the 5th, 8th, 9th, or 10th position can reverse the polarity of Cx32 hemichannel V(j)-gating. We conclude that the 1st through 10th amino acid residues lie within the transjunctional electric field and within the channel pore, as in this position they could sense changes in V(j) and be largely insensitive to changes in absolute membrane potential (V(m)). Conductive hemichannels formed by Cx32*Cx43E1 containing a negatively charged residue at either the 8th or 10th position display bi-polar V(j)-gating; that is, the open probability of hemichannels formed by these connexins is reduced at both positive and negative potentials and is maximal at intermediate voltages. In contrast, Cx32*Cx43E1 hemichannels with negative charges at either the 2nd or 5th positions are uni-polar, closing only at positive V(j). The simplest interpretation of these data is that the Cx32 hemichannel can adopt at least two different open conformations. The 1st-5th residues are located within the electric field in all open channel conformations, while the 8th and 10th residues lie within the electric field in one conformation and outside the electric field in the other conformation.
Barrio,
Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage.
1991, Pubmed,
Xenbase
Barrio,
Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage.
1991,
Pubmed
,
Xenbase
Bezrukov,
Probing alamethicin channels with water-soluble polymers. Effect on conductance of channel states.
1993,
Pubmed
Bruzzone,
Null mutations of connexin32 in patients with X-linked Charcot-Marie-Tooth disease.
1994,
Pubmed
,
Xenbase
Bukauskas,
Voltage-dependent gating of single gap junction channels in an insect cell line.
1994,
Pubmed
Bukauskas,
Heterotypic gap junction channels (connexin26-connexin32) violate the paradigm of unitary conductance.
1995,
Pubmed
Bukauskas,
Two distinct gating mechanisms in gap junction channels: CO2-sensitive and voltage-sensitive.
1997,
Pubmed
Chen,
Charges, currents, and potentials in ionic channels of one conformation.
1993,
Pubmed
Harris,
Kinetic properties of a voltage-dependent junctional conductance.
1981,
Pubmed
Hertzberg,
Topology of the Mr 27,000 liver gap junction protein. Cytoplasmic localization of amino- and carboxyl termini and a hydrophilic domain which is protease-hypersensitive.
1988,
Pubmed
Krasilnikov,
The diameter of water pores formed by colicin Ia in planar lipid bilayers.
1995,
Pubmed
Moreno,
Gap junction channels: distinct voltage-sensitive and -insensitive conductance states.
1994,
Pubmed
Obaid,
Cell-to-cell channels with two independently regulated gates in series: analysis of junctional conductance modulation by membrane potential, calcium, and pH.
1983,
Pubmed
Oh,
Changes in permeability caused by connexin 32 mutations underlie X-linked Charcot-Marie-Tooth disease.
1997,
Pubmed
,
Xenbase
Oh,
Molecular determinants of electrical rectification of single channel conductance in gap junctions formed by connexins 26 and 32.
1999,
Pubmed
Oh,
Stoichiometry of transjunctional voltage-gating polarity reversal by a negative charge substitution in the amino terminus of a connexin32 chimera.
2000,
Pubmed
,
Xenbase
Omori,
Connexin 32 mutations from X-linked Charcot-Marie-Tooth disease patients: functional defects and dominant negative effects.
1996,
Pubmed
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
Spray,
Equilibrium properties of a voltage-dependent junctional conductance.
1981,
Pubmed
,
Xenbase
Suchyna,
Different ionic selectivities for connexins 26 and 32 produce rectifying gap junction channels.
1999,
Pubmed
,
Xenbase
Swenson,
Formation of gap junctions by expression of connexins in Xenopus oocyte pairs.
1989,
Pubmed
,
Xenbase
Trexler,
Voltage gating and permeation in a gap junction hemichannel.
1996,
Pubmed
,
Xenbase
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
Verselis,
A voltage-dependent gap junction in Drosophila melanogaster.
1991,
Pubmed
Vodyanoy,
Sizing of an ion pore by access resistance measurements.
1992,
Pubmed