Functional rescue of defective mutant connexons by pairing with wild-type connexons

Hülser, Dieter F.; Rütz, Marie-Louise; Eckert, Reiner; Traub, Otto

doi:10.1007/s004240000460

Cited by 13 publications

(8 citation statements)

References 29 publications

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“…5 and 6, upper panels). This was not unexpected as we have shown previously for two other connexins, Cx45 [13] and Cx49 [17], that truncation of the C-terminus does not alter the voltage dependence of the resulting channels.…”

Section: Limitations Of Acidification Protocols For Ph-gating Experimsupporting

confidence: 68%

pH gating of lens fibre connexins

Eckert

2002

Pflugers Arch - Eur J Physiol

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Chemical gating of gap junction channels by intracellular pH may be an important mechanism for the physiological regulation of cell-cell coupling. In the ocular lens, pH gating of gap junction channels has been implicated as a possible cause of cataract in diabetics. To address this question further, I determined the pH dependence of the rat connexin (Cx)-46 and ovine Cx49 in transfected HeLa cells using the pH-clamp technique during dual whole-cell recording. pH gating for both connexins was fast and reversible. The apparent p K(a) (p K(a,app)) was 6.66 +/- 0.01 and the Hill coefficient ( n) 6.8 +/- 1.8 for Cx49, and for Cx46 6.8 +/- 0.01 and 2.2 +/- 0.15, respectively. C-terminal truncation of Cx46 by 163 aa did not abolish the pH sensitivity but shifted the p K(a,app) to 6.6 +/- 0.01. This finding is inconsistent with the ball-and-chain model proposed for Cx43. Voltage gating of Cx46 channels was also not altered by truncation or acidic pH, indicating that the two gating mechanisms are functionally and possibly structurally separate. The data also imply a significant role of pH gating for lens pathophysiology. For the normal pH range in the lens cortex (pH 6.8-7.2) most gap junction channels will be open. However, mild acidification will reduce gap junctional coupling significantly, especially for Cx50 channels. Localized closure of gap junction channels will disrupt lens transport and thus may contribute to the tissue damage observed in diabetic lenses.

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Section: Limitations Of Acidification Protocols For Ph-gating Experimsupporting

confidence: 68%

pH gating of lens fibre connexins

Eckert

2002

Pflugers Arch - Eur J Physiol

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“…In a rare example of a ‘dominant positive’ effect, ‘heterotypic’ docking of Cx45 with a CT truncation mutant of Cx45 that does not form homotypic junctional channels enables to the truncated Cx45 hemichannel to open (Hulser et al, 2001). …”

Section: Permeability Of Vascular Connexin Channelsmentioning

confidence: 99%

Chapter 2 Biological and Biophysical Properties of Vascular Connexin Channels

Johnstone

Isakson

Locke

2009

International Review of Cell and Molecular Biology

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Intercellular channels formed by connexin proteins play a pivotal role in the direct movement of ions and larger cytoplasmic solutes between vascular endothelial cells, between vascular smooth muscle cells, and between endothelial and smooth muscle cells. Multiple genetic and epigenetic factors modulate connexin expression levels and/or channel function, including cell type-independent and cell type-specific transcription factors, posttranslational modification and localized membrane targeting. Additionally, differences in protein-protein interactions, including those between connexins, significantly contribute to both vascular homeostasis and disease progression. The biophysical properties of the connexin channels identified in the vasculature, those formed by Cx37, Cx40, Cx43 and/or Cx45 proteins, are discussed in this review in the physiological and pathophysiological context of vessel function.

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“…This methodology is also a useful tool to compare the influence of cell-type and connexin-type on coupling properties, since changing the donor and recipient cells allows comparison of dye transfer efficiency by different connexin isoforms and distinct cell types (19,21,33,34,39,40). For example, using flow cytometry, Czyz and coworkers (34) observed that Cx43-transfected HeLa cells transferred calcein more efficiently than did Cx40-transfected HeLa cells.…”

Section: Flow Cytometry: a Useful Approach To Study Gap Junctional Comentioning

confidence: 99%

Flow cytometry analysis of gap junction‐mediated cell–cell communication: Advantages and pitfalls

et al. 2006

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Background: Since the first morphological description of the gap junctions use electron microscopy, a considerable number of techniques has been introduced to evaluate gap junction channel functionality, many of which use dye transfer techniques, such as dye injection and fluorescent dye transfer, analyzed by flow cytometry. Methods: To analyze dye transfer, generally one population of cells is incubated with calcein-AM (0.5 lM) for 30 min at 37°C, and the other population was incubated with the lipophilic dye DiIC 18 (3) (10 lM) for 1 h at 37°C; after incubation, these cells were washed five times with PBS and cocultured for different times, and then the dye transfer was analyzed by flow cytometry.

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Functional rescue of defective mutant connexons by pairing with wild-type connexons

Cited by 13 publications

References 29 publications

pH gating of lens fibre connexins

pH gating of lens fibre connexins

Chapter 2 Biological and Biophysical Properties of Vascular Connexin Channels

Flow cytometry analysis of gap junction‐mediated cell–cell communication: Advantages and pitfalls

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