Gain-of-function mutations in the Caenorhabditis elegans lin-1 ETS gene identify a C-terminal regulatory domain phosphorylated by ERK MAP kinase.
Genetic analysis of lin-1 loss-of-function mutations suggests that lin-1 controls multiple cell-fate decisions during Caenorhabditis elegans development and is negatively regulated by a conserved receptor tyrosine kinase-Ras-ERK mitogen-activated protein (MAP) kinase signal transduction pathway. LIN-1 protein contains an ETS domain and presumably regulates transcription. We identified and characterized six gain-of-function mutations that define a new class of lin-1 allele. These lin-1 alleles appeared to be constitutively active and unresponsive to negative regulation. Each allele has a single-base change that affects the predicted C terminus of LIN-1, suggesting this region is required for negative regulation. The C terminus of LIN-1 was a high-affinity substrate for Erk2 in vitro, suggesting that LIN-1 is directly regulated by ERK MAP kinase. Because mpk-1 ERK MAP kinase controls at least one cell-fate decision that does not require lin-1, our results suggest that MPK-1 contributes to the specificity of this receptor tyrosine kinase-Ras-MAP kinase signal transduction pathway by phosphorylating different proteins in different developmental contexts. These lin-1 mutations all affect a four-amino-acid motif, FQFP, that is conserved in vertebrate and Drosophila ETS proteins that are also phosphorylated by ERK MAP kinase. This sequence may be a substrate recognition motif for the ERK subfamily of MAP kinases.
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Jacobs
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Beitel
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Clark
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Horvitz
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Kornfeld
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers / Q000235:genetics; D018509:DNA, Helminth / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000235:genetics; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics; D014844:Vulva / Q000002:abnormalities
D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D018509:DNA, Helminth; D015801:Helminth Proteins; C097533:Lin-1 protein, C elegans; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases