Chemical and Voltage Gating of Gap Junction Channels Expressed in Xenopus Oocytes

2020 ◽  
Author(s):  
Camillo Peracchia
Keyword(s):  
Gap Junction ◽  
Xenopus Oocytes ◽  
Voltage Gating ◽  
Gap Junction Channels

scholarly journals Stochastic 16-State Model of Voltage Gating of Gap-Junction Channels Enclosing Fast and Slow Gates

2012 ◽  
Vol 102 (11) ◽  
pp. 2471-2480 ◽  
Author(s):  
Nerijus Paulauskas ◽  
Henrikas Pranevicius ◽  
Jonas Mockus ◽  
Feliksas F. Bukauskas
Keyword(s):  
Gap Junction ◽  
Voltage Gating ◽  
State Model ◽  
Gap Junction Channels

scholarly journals A Stochastic Model of Voltage-Gating of Connexin-Based Gap Junction Channels Containing Fast and Slow Gates

2011 ◽  
Vol 100 (3) ◽  
pp. 564a
Author(s):  
Nerijus Paulauskas ◽  
Henrikas Pranevicius ◽  
Feliksas Bukauskas
Keyword(s):  
Stochastic Model ◽  
Gap Junction ◽  
Voltage Gating ◽  
Gap Junction Channels

Continuous Time Markov Chain Models of Voltage Gating of Gap Junction Channels

2014 ◽  
Vol 43 (2) ◽  
Author(s):  
H. Pranevicius ◽  
M. Pranevicius ◽  
O. Pranevicius ◽  
M. Snipas ◽  
N. Paulauskas ◽  
...  
Keyword(s):  
Markov Chain ◽  
Gap Junction ◽  
Continuous Time ◽  
Voltage Gating ◽  
Continuous Time Markov Chain ◽  
Gap Junction Channels ◽  
Markov Chain Models

scholarly journals Connexin40, a component of gap junctions in vascular endothelium, is restricted in its ability to interact with other connexins.

1993 ◽  
Vol 4 (1) ◽  
pp. 7-20 ◽  
Author(s):  
R Bruzzone ◽  
J A Haefliger ◽  
R L Gimlich ◽  
D L Paul
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Xenopus Oocytes ◽  
Immunofluorescence Microscopy ◽  
Vascular Wall ◽  
Structural Protein ◽  
Aortic Smooth Muscle ◽  
Gap Junction Channels ◽  
Intercellular Channels ◽  
Punctate Pattern

The cellular distribution of connexin40 (Cx40), a newly cloned gap junction structural protein, was examined by immunofluorescence microscopy using two different specific anti-peptide antibodies. Cx40 was detected in the endothelium of muscular as well as elastic arteries in a punctate pattern consistent with the known distribution of gap junctions. However, it was not detected in other cells of the vascular wall. By contrast, Cx43, another connexin present in the cardiovascular system, was not detected in endothelial cells of muscular arteries but was abundant in the myocardium and aortic smooth muscle. We have tested the ability of these connexins to interact functionally. Cx40 was functionally expressed in pairs of Xenopus oocytes and induced the formation of intercellular channels with unique voltage dependence. Unexpectedly, communication did not occur when oocytes expressing Cx40 were paired with those expressing Cx43, although each could interact with a different connexin, Cx37, to form gap junction channels in paired oocytes. These findings indicate that establishment of intercellular communication can be spatially regulated by the selective expression of different connexins and suggest a mechanism that may operate to control the extent of communication between cells.

scholarly journals Concatenation of Human Connexin26 (hCx26) and Human Connexin46 (hCx46) for the Analysis of Heteromeric Gap Junction Hemichannels and Heterotypic Gap Junction Channels

2018 ◽  
Vol 19 (9) ◽  
pp. 2742 ◽  
Author(s):  
Patrik Schadzek ◽  
Doris Hermes ◽  
Yannick Stahl ◽  
Nadine Dilger ◽  
Anaclet Ngezahayo
Keyword(s):  
Gap Junction ◽  
Xenopus Oocytes ◽  
Single Channel ◽  
Single Channels ◽  
Dye Transfer ◽  
Channel Conductance ◽  
Gap Junction Channels ◽  
Plaque Area ◽  
Gap Junction Hemichannels ◽  
Inside Out

Gap junction channels and hemichannels formed by concatenated connexins were analyzed. Monomeric (hCx26, hCx46), homodimeric (hCx46-hCx46, hCx26-hCx26), and heterodimeric (hCx26-hCx46, hCx46-hCx26) constructs, coupled to GFP, were expressed in HeLa cells. Confocal microscopy showed that the tandems formed gap junction plaques with a reduced plaque area compared to monomeric hCx26 or hCx46. Dye transfer experiments showed that concatenation allows metabolic transfer. Expressed in Xenopus oocytes, the inside-out patch-clamp configuration showed single channels with a conductance of about 46 pS and 39 pS for hemichannels composed of hCx46 and hCx26 monomers, respectively, when chloride was replaced by gluconate on both membrane sides. The conductance was reduced for hCx46-hCx46 and hCx26-hCx26 homodimers, probably due to the concatenation. Heteromerized hemichannels, depending on the connexin-order, were characterized by substates at 26 pS and 16 pS for hCx46-hCx26 and 31 pS and 20 pS for hCx26-hCx46. Because of the linker between the connexins, the properties of the formed hemichannels and gap junction channels (e.g., single channel conductance) may not represent the properties of hetero-oligomerized channels. However, should the removal of the linker be successful, this method could be used to analyze the electrical and metabolic selectivity of such channels and the physiological consequences for a tissue.

Opposing gates model for voltage gating of gap junction channels

2001 ◽  
Vol 281 (5) ◽  
pp. C1604-C1613 ◽  
Author(s):  
Ye Chen-Izu ◽  
Alonso P. Moreno ◽  
Robert A. Spangler
Keyword(s):  
Gap Junction ◽  
Present Model ◽  
Voltage Gating ◽  
Voltage Range ◽  
Gap Junction Channels ◽  
Gating Model ◽  
Gap Junction Channel ◽  
Intercellular Channels ◽  
Heterotypic Channels

Gap junctions are intercellular channels that link the cytoplasm of neighboring cells. Because a gap junction channel is composed of two connexons docking head-to-head with each other, the channel voltage-gating profile is symmetrical for homotypic channels made of two identical connexons (hemichannels) and asymmetric for the heterotypic channels made of two different connexons (i.e., different connexin composition). In this study we have developed a gating model that allows quantitative characterization of the voltage gating of homotypic and heterotypic channels. This model differs from the present model in use by integrating, rather than separating, the contributions of the voltage gates of the two member connexons. The gating profile can now be fitted over the entire voltage range, eliminating the previous need for data splicing and fusion of two hemichannel descriptions, which is problematic when dealing with heterotypic channels. This model also provides a practical formula to render quantitative several previously qualitative concepts, including a similarity principle for matching a voltage gate to its host connexon, assignment of gating polarity to a connexon, and the effect of docking interactions between two member connexons in an intact gap junction channel.

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