Abstract
In certain Ras mutant cell lines, the inhibition of extracellular signal-regulated kinase (ERK) signaling increases RhoA activity and inhibits cell motility, which was attributed to a decrease in Fra-1 levels. Here we report a Fra-1-independent augmentation of RhoA signaling during short-term inhibition of ERK signaling. Using mass spectrometry-based proteomics, we identified guanine exchange factor H1 (GEF-H1) as mediating this effect. ERK binds to the Rho exchange factor GEF-H1 and phosphorylates it on S959, causing inhibition of GEF-H1 activity and a consequent decrease in RhoA activity. Knockdown experiments and expression of a nonphosphorylatable S959A GEF-H1 mutant showed that this site is crucial in regulating cell motility and invasiveness. Thus, we identified GEF-H1 as a critical ERK effector that regulates motility, cell morphology, and invasiveness.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Cell Line, Tumor
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Cell Movement
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Enzyme Activation*
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Extracellular Signal-Regulated MAP Kinases / metabolism*
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HEK293 Cells
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Humans
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Molecular Sequence Data
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Mutation
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Neoplasm Invasiveness / genetics
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Neoplasm Invasiveness / pathology
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Neoplasms / genetics
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Neoplasms / metabolism
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Neoplasms / pathology
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Phosphorylation
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Proto-Oncogene Proteins c-fos / metabolism
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RNA Interference
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Rats
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Rho Guanine Nucleotide Exchange Factors / chemistry
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Rho Guanine Nucleotide Exchange Factors / genetics
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Rho Guanine Nucleotide Exchange Factors / metabolism*
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Signal Transduction
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rhoA GTP-Binding Protein / metabolism*
Substances
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ARHGEF2 protein, human
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Proto-Oncogene Proteins c-fos
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Rho Guanine Nucleotide Exchange Factors
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fos-related antigen 1
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Extracellular Signal-Regulated MAP Kinases
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rhoA GTP-Binding Protein