A Closed Gap Junction Channel State Caused By A Single Site Mutation in the 3rd Transmembrane Helix

2004 ◽  
Vol 10 (S02) ◽  
pp. 1498-1499 ◽  
Author(s):  
Derek L Beahm ◽  
Guido Gaietta ◽  
Anjana Chandrasekhar ◽  
Galen M Hand ◽  
Amy Smock ◽  
...  
Keyword(s):  
Gap Junction ◽  
Transmembrane Helix ◽  
Single Site ◽  
Site Mutation ◽  
Channel State ◽  
Gap Junction Channel

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

scholarly journals Mutation of a Conserved Threonine in the Third Transmembrane Helix of α- and β-Connexins Creates a Dominant-negative Closed Gap Junction Channel

2005 ◽  
Vol 281 (12) ◽  
pp. 7994-8009 ◽  
Author(s):  
Derek L. Beahm ◽  
Atsunori Oshima ◽  
Guido M. Gaietta ◽  
Galen M. Hand ◽  
Amy E. Smock ◽  
...  
Keyword(s):  
Gap Junction ◽  
Transmembrane Helix ◽  
Dominant Negative ◽  
The Third ◽  
Gap Junction Channel

scholarly journals Structural insights into the gating mechanism of human Cx43/GJA1 gap junction channel

2021 ◽  
Author(s):  
Jae-Sung Woo ◽  
Hyuk-Joon Lee ◽  
Hyung Jin Cha ◽  
Hyeongseop Jeong ◽  
Seu-Na Lee ◽  
...  
Keyword(s):  
Gap Junction ◽  
Conformational Changes ◽  
Transmembrane Helix ◽  
Ph Change ◽  
Structural Stabilization ◽  
Helix Formation ◽  
Gap Junction Channel ◽  
Gating Mechanism ◽  
A Cell ◽  
Structural Insights

Abstract Connexin family proteins assemble into hexameric hemichannels in a cell membrane, which dock together between two adjacent membranes to form gap junction intercellular channels (GJIChs). The most ubiquitously expressed connexin Cx43 plays important roles in numerous biological processes. Here we report cryo-EM structures of Cx43 GJIChs at 3.1–3.6 Å resolutions, which show dynamic conformational changes of N-terminal helices (NTHs) caused by pH change or C-terminal truncation. Cx43 GJIChs in a channel-closing condition contain 12 protomers in gate-covering NTH (GCN) conformation, while those in opening conditions have varying compositions of GCNs and pore-lining NTHs (PLNs) resulting in various pore dimensions and electrostatic surface potentials. GCN-to-PLN transition accompanies π-helix formation in the first transmembrane helix (TM1), movement of TM2-4 that creates a side opening to the membrane, and structural stabilization of the cytoplasmic loop. Our study provides structural insights into the intercellular ion/metabolite transfer and the lateral lipid transport through Cx43 GJICh.

scholarly journals Cholesterol modulates function of connexin 43 gap junction channel via PKC pathway in H9c2 cells

2014 ◽  
Vol 1838 (8) ◽  
pp. 2019-2025 ◽  
Author(s):  
Jun Zou ◽  
Xiao-Yang Yue ◽  
Sheng-Chao Zheng ◽  
Guangwei Zhang ◽  
He Chang ◽  
...  
Keyword(s):  
Gap Junction ◽  
Connexin 43 ◽  
H9c2 Cells ◽  
Gap Junction Channel

scholarly journals Identification of amino acid residues lining the pore of a gap junction channel

2002 ◽  
Vol 159 (2) ◽  
pp. 349-360 ◽  
Author(s):  
I.M. Skerrett ◽  
J. Aronowitz ◽  
J.H. Shin ◽  
G. Cymes ◽  
E. Kasperek ◽  
...  
Keyword(s):  
Gap Junction ◽  
Molecular Level ◽  
Close Association ◽  
Pore Wall ◽  
Van Der Waals Interactions ◽  
Amino Acid Residues ◽  
Fixed Charges ◽  
Gap Junction Channel ◽  
Multicellular Organisms ◽  
Pore Lining

Gap junctions represent a ubiquitous and integral part of multicellular organisms, providing the only conduit for direct exchange of nutrients, messengers and ions between neighboring cells. However, at the molecular level we have limited knowledge of their endogenous permeants and selectivity features. By probing the accessibility of systematically substituted cysteine residues to thiol blockers (a technique called SCAM), we have identified the pore-lining residues of a gap junction channel composed of Cx32. Analysis of 45 sites in perfused Xenopus oocyte pairs defined M3 as the major pore-lining helix, with M2 (open state) or M1 (closed state) also contributing to the wider cytoplasmic opening of the channel. Additional mapping of a close association between M3 and M4 allowed the helices of the low resolution map (Unger et al., 1999. Science. 283:1176–1180) to be tentatively assigned to the connexin transmembrane domains. Contrary to previous conceptions of the gap junction channel, the residues lining the pore are largely hydrophobic. This indicates that the selective permeabilities of this unique channel class may result from novel mechanisms, including complex van der Waals interactions of permeants with the pore wall, rather than mechanisms involving fixed charges or chelation chemistry as reported for other ion channels.

Innexin-3 forms connexin-like intercellular channels

1999 ◽  
Vol 112 (14) ◽  
pp. 2391-2396 ◽  
Author(s):  
Y. Landesman ◽  
T.W. White ◽  
T.A. Starich ◽  
J.E. Shaw ◽  
D.A. Goodenough ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Gap Junction ◽  
Functional Properties ◽  
Xenopus Oocytes ◽  
Family Members ◽  
Electrical Coupling ◽  
Large Family ◽  
Gap Junction Channel ◽  
Intercellular Channels

Innexins comprise a large family of genes that are believed to encode invertebrate gap junction channel-forming proteins. However, only two Drosophila innexins have been directly tested for the ability to form intercellular channels and only one of those was active. Here we tested the ability of Caenorhabditis elegans family members INX-3 and EAT-5 to form intercellular channels between paired Xenopus oocytes. We show that expression of INX-3 but not EAT-5, induces electrical coupling between the oocyte pairs. In addition, analysis of INX-3 voltage and pH gating reveals a striking degree of conservation in the functional properties of connexin and innnexin channels. These data strongly support the idea that innexin genes encode intercellular channels.

Is the gap junction channel -the connexon- made of connexin or ductin?

1993 ◽  
Vol 106 (2) ◽  
pp. 463-472 ◽  
Author(s):  
Malcolm E. Finbow ◽  
John D. Pitts
Keyword(s):  
Gap Junction ◽  
Gap Junction Channel

Neuroprotection in the treatment of glaucoma – A focus on connexin43 gap junction channel blockers

2015 ◽  
Vol 95 ◽  
pp. 182-193 ◽  
Author(s):  
Ying-Shan Chen ◽  
Colin R. Green ◽  
Helen V. Danesh-Meyer ◽  
Ilva D. Rupenthal
Keyword(s):  
Gap Junction ◽  
Channel Blockers ◽  
Gap Junction Channel
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