Beyond the gap: functions of unpaired connexon channels

Nat Rev Mol Cell Biol. 2003 Apr;4(4):285-94. doi: 10.1038/nrm1072.


Gap junctions consist of intercellular channels that connect the cytoplasm of adjacent cells directly and allow the exchange of small molecules. These channels are unique in that they span two plasma membranes--the more orthodox ion or ligand-gated channels span only one. Each cell contributes half of the intercellular channel, and each half is known as a connexon or hemichannel. Recent studies indicate that connexons are also active in single plasma membranes and that they might be essential in intercellular signalling beyond their incorporation into gap junctions.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Calcium Signaling / physiology
  • Charcot-Marie-Tooth Disease / genetics
  • Connexins / physiology*
  • Connexins / ultrastructure
  • Gap Junctions / physiology*
  • Gap Junctions / ultrastructure
  • Humans
  • Intercellular Junctions / physiology
  • Intercellular Junctions / ultrastructure
  • Ion Channels / physiology
  • Membrane Proteins / physiology*
  • Membrane Proteins / ultrastructure
  • Models, Biological


  • Connexins
  • Ion Channels
  • Membrane Proteins