Interaction of PAR-6 with CDC-42 is required for maintenance but not establishment of PAR asymmetry in C. elegans

Dev Biol. 2006 Nov 15;299(2):386-97. doi: 10.1016/j.ydbio.2006.08.002. Epub 2006 Aug 9.


Caenorhabditis elegans embryonic polarity requires the asymmetrically distributed proteins PAR-3, PAR-6 and PKC-3. The rho family GTPase CDC-42 regulates the activities of these proteins in mammals, flies and worms. To clarify its mode of action in C. elegans we disrupted the interaction between PAR-6 and CDC-42 in vivo, and also determined the distribution of GFP-tagged CDC-42 in the early embryo. Mutant PAR-6 proteins unable to interact with CDC-42 accumulated asymmetrically, at a reduced level, but this asymmetry was not maintained during the first division. We also determined that constitutively active GFP::CDC-42 becomes enriched in the anterior during the first cell cycle in a domain that overlaps with PAR-6. The asymmetry is dependent on PAR-2, PAR-5 and PAR-6. Furthermore, we found that overexpression of constitutively active GFP::CDC-42 increased the size of the anterior domain. We conclude that the CDC-42 interaction with PAR-6 is not required for the initial establishment of asymmetry but is required for maximal cortical accumulation of PAR-6 and to maintain its asymmetry.

Publication types

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

MeSH terms

  • 14-3-3 Proteins / metabolism
  • Amino Acid Sequence
  • Animals
  • Body Patterning
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Polarity
  • Embryo, Nonmammalian / metabolism
  • Embryo, Nonmammalian / physiology
  • Molecular Sequence Data
  • Protein Binding
  • cdc42 GTP-Binding Protein / metabolism*


  • 14-3-3 Proteins
  • Caenorhabditis elegans Proteins
  • par-2 protein, C elegans
  • par-5 protein, C elegans
  • par-6 protein, C elegans
  • cdc42 GTP-Binding Protein