RAP-1 and the RAL-1/exocyst pathway coordinate hypodermal cell organization in Caenorhabditis elegans

EMBO J. 2007 Dec 12;26(24):5083-92. doi: 10.1038/sj.emboj.7601922. Epub 2007 Nov 8.


The small Ras-like GTPase Rap1 has been identified as a regulator of integrin activation and cadherin-mediated cell-cell contacts. Surprisingly, null mutants of RAP-1 in Caenorhabditis elegans are viable and fertile. In a synthetic lethal RNAi screen with C. elegans rap-1 mutants, the Ras-like GTPase ral-1 emerged as one of seven genes specifically required for viability. Depletion of exoc-8 and sec-5, encoding two putative RAL-1 effectors and members of the exocyst complex, also caused lethality of rap-1 mutants, but did not affect wild-type worms. The RAP-1 and the RAL-1/exocyst pathway appear to coordinate hypodermal cell movement and elongation during embryonic development. They mediate their effect in part through targeting the alpha-catenin homologue HMP-1 to the lateral membrane. Genetic interactions show that the RAP-1 and RAL-1/exocyst pathway also act in parallel during larval stages. Together these data provide in vivo evidence for the exocyst complex as a downstream RAL-1 effector in cell migration.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Movement / physiology*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism
  • Embryo, Nonmammalian / anatomy & histology
  • Embryo, Nonmammalian / physiology
  • Mutation
  • Phenotype
  • RNA Interference
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Subcutaneous Tissue*
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • ral GTP-Binding Proteins / genetics
  • ral GTP-Binding Proteins / metabolism*
  • rap1 GTP-Binding Proteins / genetics
  • rap1 GTP-Binding Proteins / metabolism*


  • Caenorhabditis elegans Proteins
  • Cytoskeletal Proteins
  • Exoc-8 protein, C elegans
  • Recombinant Fusion Proteins
  • Vesicular Transport Proteins
  • RAL-1 protein, C elegans
  • ral GTP-Binding Proteins
  • rap1 GTP-Binding Proteins