The ksr-1 gene encodes a novel protein kinase involved in Ras-mediated signaling in C. elegans.
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.
Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology / Q000201:enzymology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004627:Embryonic Induction; D005260:Female; D017238:Genes, Helminth / Q000235:genetics*; D016153:Genes, Suppressor / Q000235:genetics; D015801:Helminth Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D018510:RNA, Helminth / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D014844:Vulva / Q000196:embryology; D018631:ras Proteins / Q000502:physiology*
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D018510:RNA, Helminth; D012333:RNA, Messenger; C066646:let-60 protein, C elegans; D011494:Protein Kinases; C097199:KSR-1 protein kinase; D018631:ras Proteins