The ksr-1 gene encodes a novel protein kinase involved in Ras-mediated signaling in C. elegans

Cell. 1995 Dec 15;83(6):903-13. doi: 10.1016/0092-8674(95)90206-6.


By screening for mutations that suppress the vulval defects caused by a constitutively active let-60 ras gene, we identified six loss-of-function alleles of ksr-1, a novel C. elegans gene. Our genetic analysis showed ksr-1 positively mediates Ras signaling and functions downstream of or in parallel to let-60. In the absence of ksr-1 function, normal Ras signaling is impaired only slightly, suggesting ksr-1 may act to modulate, or in a branch that diverges from, the main signaling pathway. The predicted KSR-1 protein has a protein kinase domain and is most similar to a recently identified Drosophila protein involved in Ras signaling. We propose that the function of ksr-1 is evolutionarily conserved.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / enzymology
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins*
  • Chromosome Mapping
  • Cloning, Molecular
  • Embryonic Induction
  • Female
  • Genes, Helminth / genetics*
  • Genes, Suppressor / genetics
  • Helminth Proteins / genetics
  • Molecular Sequence Data
  • Mutation
  • Protein Kinases / chemistry
  • Protein Kinases / genetics*
  • Protein Kinases / physiology
  • RNA, Helminth / analysis
  • RNA, Messenger / analysis
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Signal Transduction / physiology*
  • Vulva / embryology
  • ras Proteins / physiology*


  • Caenorhabditis elegans Proteins
  • Helminth Proteins
  • RNA, Helminth
  • RNA, Messenger
  • let-60 protein, C elegans
  • Protein Kinases
  • KSR-1 protein kinase
  • ras Proteins

Associated data

  • GENBANK/S80647