Where are the gates in gap junction channels?

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

1. In the formation and function of gap junction channels two types of gates ought to be discriminated: the docking gate and the channel gates proper. The docking gate is involved in the transformation of a closed hemichannel to a patent gap junction channel. By definition the trigger mechanism for this gate and maybe even the gate itself is contained within the extracellular loops of the gap junction proteins, the connexins. The channel gates proper determine the open and closed states of the complete gap junction channels. 2. Probing the docking gate by mutagenesis of connexins and by synthetic peptides indicates that this gate is the consequence of complex interactions between a large fraction of the amino acids comprising the extracellular loops. Probably both inter- and infra-molecular interactions are involved, and disulfide exchange may be entailed in the stabilization of the open and closed states. 3. of the various effecters on the channel gate(s) the voltage effects have obtained the most scrutiny to date. The response of gap junction channels and hemichannels is diverse, the various channels respond differently to transjunctional and membrane potential. No equivalent to the 54 segment representing the voltage sensor in other voltage dependent ion channels is present in the connexin sequences, instead mutations in various segments of connexins have been reported to affect the voltage dependence of gap junction channels. To understand the complexity of voltage effects on gap junction channels, non-connexin peptides may need to be considered as voltage sensors or as modifiers thereof.

Original languageEnglish (US)
Pages (from-to)1047-1052
Number of pages6
JournalClinical and Experimental Pharmacology and Physiology
Volume23
Issue number12
DOIs
StatePublished - Jan 1 1996

Keywords

  • Connexin
  • Docking gate
  • Gap junction
  • Voltage gate

ASJC Scopus subject areas

  • Physiology
  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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