Innexins: members of an evolutionarily conserved family of gap-junction proteins

Biochim Biophys Acta. 2005 Jun 10;1711(2):225-45. doi: 10.1016/j.bbamem.2004.10.004. Epub 2004 Nov 17.


Gap junctions are clusters of intercellular channels that provide cells, in all metazoan organisms, with a means of communicating directly with their neighbours. Surprisingly, two gene families have evolved to fulfil this fundamental, and highly conserved, function. In vertebrates, gap junctions are assembled from a large family of connexin proteins. Innexins were originally characterized as the structural components of gap junctions in Drosophila, an arthropod, and the nematode Caenorhabditis elegans. Since then, innexin homologues have been identified in representatives of the other major invertebrate phyla and in insect-associated viruses. Intriguingly, functional innexin homologues have also been found in vertebrate genomes. These studies have informed our understanding of the molecular evolution of gap junctions and have greatly expanded the numbers of model systems available for functional studies. Genetic manipulation of innexin function in relatively simple cellular systems should speed progress not only in defining the importance of gap junctions in a variety of biological processes but also in elucidating the mechanisms by which they act.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Evolution
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans Proteins / genetics
  • Connexins / genetics*
  • Connexins / physiology
  • Drosophila Proteins / genetics
  • Drosophila Proteins / physiology
  • Drosophila melanogaster / growth & development
  • Gap Junctions / genetics*
  • Gap Junctions / physiology
  • Humans
  • Ion Channels / physiology
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • Mutation
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology
  • Phenotype
  • Sequence Alignment


  • Caenorhabditis elegans Proteins
  • Connexins
  • Drosophila Proteins
  • Ion Channels
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Unc-7 protein, C elegans
  • Unc-9 protein, C elegans
  • inx2 protein, Drosophila
  • ogre protein, Drosophila
  • shakB protein, Drosophila