scholarly journals The connexin family of intercellular channel forming proteins

1995 ◽  
Vol 48 (4) ◽  
pp. 1148-1157 ◽  
Author(s):  
Thomas W. White ◽  
Roberto Bruzzone ◽  
David L. Paul
Keyword(s):  
Intercellular Channel

Nonredundant Gap Junction Functions

Physiology ◽  
2003 ◽  
Vol 18 (3) ◽  
pp. 95-99 ◽  
Author(s):  
Thomas W. White
Keyword(s):  
Gap Junction ◽  
Molecular Heterogeneity ◽  
Channel Gene ◽  
Channel Proteins ◽  
Gap Junction Channel ◽  
Gap Junction Communication ◽  
Intercellular Channel ◽  
Functional Replacement

The need for molecular heterogeneity of gap junction channel proteins in vivo has been enigmatic. Recently, functional replacement of one channel gene with another in mice and flies has revealed that cellular health depends not simply on gap junction communication but also requires the correct type of intercellular channel subunit.

scholarly journals Targeted Ablation of Connexin50 in Mice Results in Microphthalmia and Zonular Pulverulent Cataracts

1998 ◽  
Vol 143 (3) ◽  
pp. 815-825 ◽  
Author(s):  
Thomas W. White ◽  
Daniel A. Goodenough ◽  
David L. Paul
Keyword(s):  
Cell Types ◽  
Targeted Deletion ◽  
Gap Junctional Communication ◽  
Eye Growth ◽  
Lens Fibers ◽  
Lens Transparency ◽  
Junctional Communication ◽  
Epithelial Junctions ◽  
Gap Junctional ◽  
Intercellular Channel

In the ocular lens, gap junctional communication is a key component of homeostatic mechanisms preventing cataract formation. Gap junctions in rodent lens fibers contain two known intercellular channel-forming proteins, connexin50 (Cx50) and Cx46. Since targeted ablation of Cx46 has been shown to cause senile-type nuclear opacities, it appears that Cx50 alone cannot meet homeostatic requirements. To determine if lens pathology arises from a reduction in levels of communication or the loss of a connexin-specific function, we have generated mice with a targeted deletion of the Cx50 gene. Cx50-null mice exhibited microphthalmia and nuclear cataracts. At postnatal day 14 (P14), Cx50-knockout eyes weighed 32% less than controls, whereas lens mass was reduced by 46%. Cx50-knockout lenses also developed zonular pulverulent cataracts, and lens abnormalities were detected by P7. Deletion of Cx50 did not alter the amounts or distributions of Cx46 or Cx43, a component of lens epithelial junctions. In addition, intercellular passage of tracers revealed the persistence of communication between all cell types in the Cx50-knockout lens. These results demonstrate that Cx50 is required not only for maintenance of lens transparency but also for normal eye growth. Furthermore, these data indicate that unique functional properties of both Cx46 and Cx50 are required for proper lens development.

scholarly journals PATHS OF TRANSTUBULAR WATER FLOW IN ISOLATED RENAL COLLECTING TUBULES

1969 ◽  
Vol 41 (2) ◽  
pp. 562-576 ◽  
Author(s):  
Jared J. Grantham ◽  
Charles E. Ganote ◽  
Maurice B. Burg ◽  
Jack Orloff
Keyword(s):  
Water Flow ◽  
Direct Evidence ◽  
Extracellular Fluid ◽  
Isotonic Solution ◽  
Intercellular Spaces ◽  
Osmotic Swelling ◽  
Induced Flow ◽  
Collecting Tubules ◽  
Intercellular Channel ◽  
Hydrostatic Pressure Difference

The cells of perfused rabbit collecting tubules swell and the intercellular spaces widen during osmotic flow of water from lumen to bath induced by antidiuretic hormone (ADH). Ouabain had no influence on these changes. In the absence of net water flow intercellular width was unaffected when tubules were swollen in hypotonic external media. Therefore, during ADH-induced flow widening of intercellular spaces is not a consequence of osmotic swelling of a closed intercellular compartment containing trapped solutes, but rather is due to flow of solution through the channel. Direct evidence of intercellular flow was obtained. Nonperfused tubules swollen in hypotonic media were reimmersed in isotonic solution with resultant entry of water into intercellular spaces. The widened spaces gradually collapsed completely. Spaces enlarged in this manner could be emptied more rapidly by increasing the transtubular hydrostatic pressure difference. In electron micrographs a path of exit of sufficient width to accommodate the observed rate of fluid flow was seen at the base of the intercellular channel. It is concluded that the intercellular spaces communicate with the external extracellular fluid and that water, having entered the cells across the luminal plasma membrane in response in ADH, leaves the cells by osmosis across both the lateral and basilar surface membranes.

Three-Dimensional Structure of the Gap Junction Connexon and Intercellular Channel

1997 ◽  
Vol 3 (S2) ◽  
pp. 227-228
Author(s):  
Guy Perkins ◽  
Dan Goodenough ◽  
Gina Sosinsky
Keyword(s):  
Small Molecules ◽  
Gap Junction ◽  
Three Dimensional ◽  
Surface Topology ◽  
Dimensional Structure ◽  
Cell Contact ◽  
Membrane Channels ◽  
Membrane Channel ◽  
Contact Areas ◽  
Intercellular Channel

Gap junctions are specialized cell-cell contact areas by which cells communication with each other. Within these contact areas are tens to thousands of membrane channels. A gap junction membrane channel (also referred to as an intercellular channel) is unique among membrane channels in that it is composed of two oligomers with each of two adjacent tissue cells contributing one oligomer (called a connexon or hemichannel). The pore of the intercellular channel controls the passage of small molecules and ions from one cell to another.We are interested in how the structure and surface topology of the gap junction connexon at its extracellular surface influences the docking and formation of an intercellular communicating channel. It has been demonstrated that connexons made from some connexins will dock and form functional channels with some but not all connexons made from other isoforms. This selectivity is surprising considering that the primary sequences of the docking domains are highly conserved.

scholarly journals Structure of components of an intercellular channel complex in sporulating Bacillus subtilis

2012 ◽  
Vol 109 (14) ◽  
pp. 5441-5445 ◽  
Author(s):  
V. M. Levdikov ◽  
E. V. Blagova ◽  
A. McFeat ◽  
M. J. Fogg ◽  
K. S. Wilson ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Intercellular Channel

Myocardial connexin-43 is upregulated in response to acute cardiac injury in rats

2017 ◽  
Vol 95 (8) ◽  
pp. 911-919 ◽  
Author(s):  
Csilla Viczenczova ◽  
Branislav Kura ◽  
Kiranj K. Chaudagar ◽  
Barbara Szeiffova Bacova ◽  
Tamara Egan Benova ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Subcutaneous Injection ◽  
Connexin 43 ◽  
Wistar Rats ◽  
Cardiac Injury ◽  
Rat Hearts ◽  
Heart Injury ◽  
Chest Irradiation ◽  
Intercellular Channel ◽  
Malignant Arrhythmias

We aimed to explore whether myocardial intercellular channel protein connexin-43 (Cx43) along with PKCε and MMP-2 might be implicated in responses to acute cardiac injury induced by 2 distinct sublethal interventions in Wistar rats. Animals underwent either single chest irradiation at dose of 25 Gy or subcutaneous injection of isoproterenol (ISO, 120 mg/kg) and were compared with untreated controls. Forty-two days post-interventions, the hearts were excised and left ventricles were used for analysis. The findings showed an increase of total as well as phosphorylated forms of myocardial Cx43 regardless of the type of interventions. Enhanced phosphorylation of Cx43 coincided with increased PKCε expression in both models. Elevation of Cx43 was associated with its enhanced distribution on lateral surfaces of the cardiomyocytes in response to both interventions, while focal areas of fibrosis without Cx43 were found in post-ISO but not post-irradiated rat hearts. In parallel, MMP-2 activity was decreased in the former while increased in the latter. Cardiac function was maintained and the susceptibility of the hearts to ischemia or malignant arrhythmias was not deteriorated 42 days after interventions when compared with controls. Altogether, the findings indicate that myocardial Cx43 is most likely implicated in potentially salutary responses to acute heart injury.

Formation of the gap junction intercellular channel requires a 30° rotation for interdigitating two apposing connexons

1998 ◽  
Vol 277 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Guy A Perkins ◽  
Daniel A Goodenough ◽  
Gina E Sosinsky
Keyword(s):  
Gap Junction ◽  
Intercellular Channel
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