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This Article Full Text Full Text (PDF) Supplemental data All Versions of this Article: 576/3/787    most recent jphysiol.2006.113837v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dong, L. Articles by Ebihara, L. Search for Related Content PubMed PubMed Citation Articles by Dong, L. Articles by Ebihara, L. Related Collections Cellular

Departments of
¹ Physiology & Biophysics
² Cell Biology & Anatomy, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA

Previous studies have shown that gap junctional channels formed from the lens connexins Cx50 (or its chicken orthologue, Cx45.6) and Cx43 exhibit marked differences in transjunctional voltage gating and unitary conductance. In the present study, we used the negatively charged dye, Lucifer Yellow (LY), to examine and compare quantitative differences in dye transfer between pairs of HeLa cells stably transfected with Cx45.6 or Cx43. Our results show that Cx45.6 gap junctional channels are three times less permeable to LY than Cx43 channels. Replacement of the N-terminus of Cx45.6 with the corresponding domain of Cx43 increased LY permeability, reduced the transjunctional voltage (V_j) gating sensitivity, and reduced the unitary conductance of Cx45.6–43N gap junctional channels. Further experiments, using a series of Alexa probes that had similar net charge but varied in size showed that the Cx45.6–43N had a significantly higher permeability for the two largest Alexa dyes than Cx45.6. These data suggest that the N-terminus plays a critical role in determining many of biophysical properties of Cx45.6 gap junctional channels, including molecular permeability and voltage gating.

(Received 18 May 2006; accepted after revision 23 August 2006; first published online 24 August 2006)
Corresponding author L. Ebihara, Department of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA. Email: lisa.ebihara{at}rosalindfranklin.edu

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