Gap Junction Currents and Countercurrents

For this special issue of Bioelectricity, I have focused on our early studies involving voltage sensitivity of gap junctions, stressing possible consequences for the establishment or maintenance of communication compartments during development. I also describe how the progressive new tools in those and subsequent studies have led to the realization that gap junction channels have connexin-specific properties and that confer upon them differential sensitivities to gating stimuli. Moreover, mutations in connexin sequences and posttranslational modifications can alter these intrinsic properties and their interaction with binding partners, contributing to pathological conditions. Numerous fundamental questions remain to be resolved, and the field badly needs highly potent and selective pharmacological reagents to distinguish nonjunctional connexin channels from other membrane pores.