Heterotypic gap junction channels (connexin26-connexin32) violate the paradigm of unitary conductance

Pflugers Arch. 1995 Apr;429(6):870-2. doi: 10.1007/BF00374812.


Human HeLa cells transfected with mouse DNA coding for connexin26 (Cx26) or connexin32 (Cx32) were used to examine the properties of heterotypic Cx26-Cx32 gap junction channels. Intercellular current flow was examined in induced cell pairs by means of the dual voltage-clamp method. We found that Cx26-Cx32 channels exhibit voltage-dependent conductances, gamma j: gamma j(main state) increases with increasing positivity at the cytoplasmic aspect of the Cx26 connexon and decreases with increasing negativity (slope: 32 pS/100 mV; gamma j(main state) reaches 48 pS as Vj approaches 0 mV); gamma j(residual state) with a similar Vj-dependence is present when the cytoplasmic end of Cx26 connexon is positive, but absent when it is negative. The single channel data provide an explanation for the asymmetric relationships between the gap junction conductance, gj, and Vj. The results are consistent with the notion that docking of two connexons co-determines the biophysical properties of a gap junction channel.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Connexin 26
  • Connexins / genetics
  • Connexins / physiology*
  • Electric Conductivity
  • Gap Junctions / physiology*
  • HeLa Cells
  • Humans
  • Mice
  • Transfection


  • Connexins
  • GJB2 protein, human
  • connexin 32
  • Connexin 26