Quantification of gap junction selectivity

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Gap junctions, which are essential for functional coordination and homeostasis within tissues, permit the direct intercellular exchange of small molecules. The abundance and diversity of this exchange depends on the number and selectivity of the comprising channels and on the transjunctional gradient for and chemical character of the permeant molecules. Limited knowledge of functionally significant permeants and poor detectability of those few that are known have made it difficult to define channel selectivity. Presented herein is a multifaceted approach to the quantification of gap junction selectivity that includes determination of the rate constant for intercellular diffusion of a fluorescent probe (k2-DYE) and junctional conductance (gj) for each junction studied, such that the selective permeability (k 2-DYE/gj) for dyes with differing chemical characteristics or junctions with differing connexin (Cx) compositions (or treatment conditions) can be compared. In addition, selective permeability can be correlated using single-channel conductance when this parameter is also measured. Our measurement strategy is capable of detecting 1) rate constants and selective permeabilities that differ across three orders of magnitude and 2) acute changes in that rate constant. Using this strategy, we have shown that 1) the selective permeability of Cx43 junctions to a small cationic dye varied across two orders of magnitude, consistent with the hypothesis that the various channel configurations adopted by Cx43 display different selective permeabilities; and 2) the selective permeability of Cx37 vs. Cx43 junctions was consistently and significantly lower.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume289
Issue number6 58-6
DOIs
StatePublished - Dec 2005

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Connexin 43
Gap Junctions
Permeability
Rate constants
Tissue homeostasis
Coloring Agents
Connexins
Molecules
Fluorescent Dyes
Chemical analysis
Homeostasis

Keywords

  • Connexin 37
  • Connexin 43
  • Diffusion rate constant

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

Cite this

Quantification of gap junction selectivity. / Ek Vitorin, Jose F; Burt, Janis M.

In: American Journal of Physiology - Cell Physiology, Vol. 289, No. 6 58-6, 12.2005.

Research output: Contribution to journalArticle

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