scholarly journals Connexin 46 and connexin 50 gap junction channel properties are shaped by structural and dynamic features of their N‐terminal domains

2021 ◽  
Author(s):  
Benny Yue ◽  
Bassam G. Haddad ◽  
Umair Khan ◽  
Honghong Chen ◽  
Mena Atalla ◽  
...  
Keyword(s):  
Gap Junction ◽  
Dynamic Features ◽  
Gap Junction Channel ◽  
Connexin 50 ◽  
Channel Properties ◽  
Terminal Domains

scholarly journals Differential regulation of distinct types of gap junction channels by similar phosphorylating conditions.

1995 ◽  
Vol 6 (12) ◽  
pp. 1707-1719 ◽  
Author(s):  
B R Kwak ◽  
M M Hermans ◽  
H R De Jonge ◽  
S M Lohmann ◽  
H J Jongsma ◽  
...  
Keyword(s):  
Gap Junction ◽  
Single Channel ◽  
Cell Communication ◽  
Differential Regulation ◽  
Cell Coupling ◽  
Gap Junction Channels ◽  
Physiological Importance ◽  
Gap Junction Channel ◽  
Conductance States ◽  
Channel Properties

Studies on physiological modulation of intercellular communication mediated by protein kinases are often complicated by the fact that cells express multiple gap junction proteins (connexins; Cx). Changes in cell coupling can be masked by simultaneous opposite regulation of the gap junction channel types expressed. We have examined the effects of activators and inhibitors of protein kinase A (PKA), PKC, and PKG on permeability and single channel conductance of gap junction channels composed of Cx45, Cx43, or Cx26 subunits. To allow direct comparison between these Cx, SKHep1 cells, which endogenously express Cx45, were stably transfected with cDNAs coding for Cx43 or Cx26. Under control conditions, the distinct types of gap junction channels could be distinguished on the basis of their permeability and single channel properties. Under various phosphorylating conditions, these channels behaved differently. Whereas agonists/antagonist of PKA did not affect permeability and conductance of all gap junction channels, variable changes were observed under PKC stimulation. Cx45 channels exhibited an additional conductance state, the detection of the smaller conductance states of Cx43 channels was favored, and Cx26 channels were less often observed. In contrast to the other kinases, agonists/antagonist of PKG affected permeability and conductance of Cx43 gap junction channels only. Taken together, these results show that distinct types of gap junction channels are differentially regulated by similar phosphorylating conditions. This differential regulation may be of physiological importance during modulation of cell-to-cell communication of more complex cell systems.

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

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 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
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