Neurons and β-cells of the pancreas express connexin36, forming gap junction channels that exhibit strong cationic selectivity

Feliksas F. Bukauskas

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We examined the permeability of connexin36 (Cx36) homotypic gap junction (GJ) channels, expressed in neurons and β-cells of the pancreas, to dyes differing in molecular mass and net charge. Experiments were performed in HeLa cells stably expressing Cx36 tagged with EGFP by combining a dual whole-cell voltage clamp and fluorescence imaging. To assess the permeability of the single GJ channel (Pγ), we used a dual-mode excitation of fluorescent dyes that allowed us to measure cell-to-cell dye transfer at levels not resolvable using whole-field excitation solely. We demonstrate that P γ of Cx36 for cationic dyes (EAM-1+ and EAM-2 +) is ~10-fold higher than that for an anionic dye of the same net charge and similar molecular mass, Alexa fluor-350 (AFl-350-). In addition, Pγ for Lucifer yellow (LY2-) is approximately fourfold smaller than that for AFl-350-, which suggests that the higher negativity of LY2- significantly reduces permeability. The Pγ of Cx36 for AFl-350 is approximately 358, 138, 23 and four times smaller than the Pγs of Cx43, Cx40, Cx45, and Cx57, respectively. In contrast, it is 6.5-fold higher than the P γ of mCx30.2, which exhibits a smaller single-channel conductance. Thus, Cx36 GJs are highly cation-selective and should exhibit relatively low permeability to numerous vital negatively charged metabolites and high permeability to K+, a major charge carrier in cell-cell communication.

Original languageEnglish (US)
Pages (from-to)243-253
Number of pages11
JournalJournal of Membrane Biology
Volume245
Issue number5-6
DOIs
StatePublished - Jun 2012

Fingerprint

Gap Junctions
Pancreas
Permeability
Neurons
Coloring Agents
Connexin 43
Optical Imaging
Fluorescent Dyes
HeLa Cells
Cell Communication
Cations
connexin 36

Keywords

  • Cationic selectivity
  • Connexin
  • Gap junction
  • Intercellular communication
  • Permeability
  • Voltage gating

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

Cite this

Neurons and β-cells of the pancreas express connexin36, forming gap junction channels that exhibit strong cationic selectivity. / Bukauskas, Feliksas F.

In: Journal of Membrane Biology, Vol. 245, No. 5-6, 06.2012, p. 243-253.

Research output: Contribution to journalArticle

@article{cedfec1cd5e148b3b8c59e5398f47564,
title = "Neurons and β-cells of the pancreas express connexin36, forming gap junction channels that exhibit strong cationic selectivity",
abstract = "We examined the permeability of connexin36 (Cx36) homotypic gap junction (GJ) channels, expressed in neurons and β-cells of the pancreas, to dyes differing in molecular mass and net charge. Experiments were performed in HeLa cells stably expressing Cx36 tagged with EGFP by combining a dual whole-cell voltage clamp and fluorescence imaging. To assess the permeability of the single GJ channel (Pγ), we used a dual-mode excitation of fluorescent dyes that allowed us to measure cell-to-cell dye transfer at levels not resolvable using whole-field excitation solely. We demonstrate that P γ of Cx36 for cationic dyes (EAM-1+ and EAM-2 +) is ~10-fold higher than that for an anionic dye of the same net charge and similar molecular mass, Alexa fluor-350 (AFl-350-). In addition, Pγ for Lucifer yellow (LY2-) is approximately fourfold smaller than that for AFl-350-, which suggests that the higher negativity of LY2- significantly reduces permeability. The Pγ of Cx36 for AFl-350 is approximately 358, 138, 23 and four times smaller than the Pγs of Cx43, Cx40, Cx45, and Cx57, respectively. In contrast, it is 6.5-fold higher than the P γ of mCx30.2, which exhibits a smaller single-channel conductance. Thus, Cx36 GJs are highly cation-selective and should exhibit relatively low permeability to numerous vital negatively charged metabolites and high permeability to K+, a major charge carrier in cell-cell communication.",
keywords = "Cationic selectivity, Connexin, Gap junction, Intercellular communication, Permeability, Voltage gating",
author = "Bukauskas, {Feliksas F.}",
year = "2012",
month = "6",
doi = "10.1007/s00232-012-9445-3",
language = "English (US)",
volume = "245",
pages = "243--253",
journal = "Journal of Membrane Biology",
issn = "0022-2631",
publisher = "Springer New York",
number = "5-6",

}

TY - JOUR

T1 - Neurons and β-cells of the pancreas express connexin36, forming gap junction channels that exhibit strong cationic selectivity

AU - Bukauskas, Feliksas F.

PY - 2012/6

Y1 - 2012/6

N2 - We examined the permeability of connexin36 (Cx36) homotypic gap junction (GJ) channels, expressed in neurons and β-cells of the pancreas, to dyes differing in molecular mass and net charge. Experiments were performed in HeLa cells stably expressing Cx36 tagged with EGFP by combining a dual whole-cell voltage clamp and fluorescence imaging. To assess the permeability of the single GJ channel (Pγ), we used a dual-mode excitation of fluorescent dyes that allowed us to measure cell-to-cell dye transfer at levels not resolvable using whole-field excitation solely. We demonstrate that P γ of Cx36 for cationic dyes (EAM-1+ and EAM-2 +) is ~10-fold higher than that for an anionic dye of the same net charge and similar molecular mass, Alexa fluor-350 (AFl-350-). In addition, Pγ for Lucifer yellow (LY2-) is approximately fourfold smaller than that for AFl-350-, which suggests that the higher negativity of LY2- significantly reduces permeability. The Pγ of Cx36 for AFl-350 is approximately 358, 138, 23 and four times smaller than the Pγs of Cx43, Cx40, Cx45, and Cx57, respectively. In contrast, it is 6.5-fold higher than the P γ of mCx30.2, which exhibits a smaller single-channel conductance. Thus, Cx36 GJs are highly cation-selective and should exhibit relatively low permeability to numerous vital negatively charged metabolites and high permeability to K+, a major charge carrier in cell-cell communication.

AB - We examined the permeability of connexin36 (Cx36) homotypic gap junction (GJ) channels, expressed in neurons and β-cells of the pancreas, to dyes differing in molecular mass and net charge. Experiments were performed in HeLa cells stably expressing Cx36 tagged with EGFP by combining a dual whole-cell voltage clamp and fluorescence imaging. To assess the permeability of the single GJ channel (Pγ), we used a dual-mode excitation of fluorescent dyes that allowed us to measure cell-to-cell dye transfer at levels not resolvable using whole-field excitation solely. We demonstrate that P γ of Cx36 for cationic dyes (EAM-1+ and EAM-2 +) is ~10-fold higher than that for an anionic dye of the same net charge and similar molecular mass, Alexa fluor-350 (AFl-350-). In addition, Pγ for Lucifer yellow (LY2-) is approximately fourfold smaller than that for AFl-350-, which suggests that the higher negativity of LY2- significantly reduces permeability. The Pγ of Cx36 for AFl-350 is approximately 358, 138, 23 and four times smaller than the Pγs of Cx43, Cx40, Cx45, and Cx57, respectively. In contrast, it is 6.5-fold higher than the P γ of mCx30.2, which exhibits a smaller single-channel conductance. Thus, Cx36 GJs are highly cation-selective and should exhibit relatively low permeability to numerous vital negatively charged metabolites and high permeability to K+, a major charge carrier in cell-cell communication.

KW - Cationic selectivity

KW - Connexin

KW - Gap junction

KW - Intercellular communication

KW - Permeability

KW - Voltage gating

UR - http://www.scopus.com/inward/record.url?scp=84864356601&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84864356601&partnerID=8YFLogxK

U2 - 10.1007/s00232-012-9445-3

DO - 10.1007/s00232-012-9445-3

M3 - Article

C2 - 22752717

AN - SCOPUS:84864356601

VL - 245

SP - 243

EP - 253

JO - Journal of Membrane Biology

JF - Journal of Membrane Biology

SN - 0022-2631

IS - 5-6

ER -