UNC-1 regulates gap junctions important to locomotion in C. elegans

Curr Biol. 2007 Aug 7;17(15):1334-9. doi: 10.1016/j.cub.2007.06.060. Epub 2007 Jul 19.


In C. elegans, loss-of-function (lf) mutations of the stomatin-like protein (SLP) UNC-1 and the innexin UNC-9 inhibit locomotion [1, 2] and modulate sensitivity to volatile anesthetics [3, 4]. It was unknown why unc-1(lf) and unc-9(lf) mutants have similar phenotypes. We tested the hypothesis that UNC-1 is a regulator of gap junctions formed by UNC-9. Analyses of junctional currents between body-wall muscle cells showed that electrical coupling was inhibited to a similar degree in unc-1(lf), unc-9(lf), and unc-1(lf);unc-9(lf) double mutants, suggesting that UNC-1 and UNC-9 function together. Expression of Punc-1::DsRED2 and Punc-9::GFP transcriptional fusions suggests that unc-1 and unc-9 are coexpressed in neurons and body-wall muscle cells. Immunohistochemistry showed that UNC-1 and UNC-9 colocalized at intercellular junctions and that unc-1(lf) did not alter UNC-9 expression or subcellular localization. Bimolecular fluorescence complementation (BiFC) assays suggest that UNC-1 and UNC-9 are physically very close at intercellular junctions. Targeted rescue experiments suggest that UNC-9 and UNC-1 function predominantly in neurons to control locomotion. Thus, in addition to the recently reported function of regulating mechanosensitive ion channels [5, 6], SLPs might have a novel function of regulating gap junctions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / analysis
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology*
  • Gap Junctions / metabolism*
  • Locomotion / physiology
  • Membrane Proteins / analysis
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Molecular Sequence Data
  • Muscle Cells / physiology
  • Neurons / physiology


  • Caenorhabditis elegans Proteins
  • Membrane Proteins
  • Unc-1 protein, C elegans
  • Unc-9 protein, C elegans

Associated data

  • GENBANK/ABQ08183
  • GENBANK/EF538426