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Phosphorylation of Shc by Src family kinases is necessary for stem cell factor receptor/c-kit mediated activation of the Ras/MAP kinase pathway and c-fos induction

Lennartsson, Johan; Blume-Jensen, Peter; Hermanson, Monica; Pontén, Emma; Carlberg, Monica and Rönnstrand, Lars LU (1999) In Oncogene 18(40). p.5546-5553
Abstract
In this report we show that Tyr568 and Tyr570 are phosphorylated in vivo in the Kit/stem cell factor receptor (Kit/SCFR) following ligand-stimulation. By mutation of Tyr568 and Tyr570 to phenylalanine residues and expression of the mutated receptors in porcine aortic endothelial (PAE) cells, we could demonstrate a loss of activation of members of the Src family of tyrosine kinases when Tyr568 was mutated, while mutation of Tyr570 only led to a minor decrease in activation of Src family members. Mutation of both tyrosine residues led to a complete loss of Src family kinase activation. Phosphorylation of the adapter protein Shc by growth factor receptors provides association sites for Grb2-Sos, thereby activating the Ras/MAP kinase pathway.... (More)
In this report we show that Tyr568 and Tyr570 are phosphorylated in vivo in the Kit/stem cell factor receptor (Kit/SCFR) following ligand-stimulation. By mutation of Tyr568 and Tyr570 to phenylalanine residues and expression of the mutated receptors in porcine aortic endothelial (PAE) cells, we could demonstrate a loss of activation of members of the Src family of tyrosine kinases when Tyr568 was mutated, while mutation of Tyr570 only led to a minor decrease in activation of Src family members. Mutation of both tyrosine residues led to a complete loss of Src family kinase activation. Phosphorylation of the adapter protein Shc by growth factor receptors provides association sites for Grb2-Sos, thereby activating the Ras/MAP kinase pathway. A much lowered degree of Shc phosphorylation, Ras and Erk2 activation and c-fos induction was seen in the Y568F mutant, while in the Y570F mutant these responses were less affected. In contrast, the mitogenic response was only slightly reduced. In a mutant receptor with both Tyr568 and Tyr570 mutated to phenylalanine residues, no phosphorylation of Shc and no activation of Ras and Erk2 was seen in response to stem cell factor stimulation, very weak induction of c-fos was seen and the mitogenic response was severely depressed. These data show that Ras/MAP kinase activation and c-fos induction by Kit/SCFR are mediated by members of the Src family kinases. However, the mitogenic response is only to a minor extent dependent on Src kinase activity. (Less)
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@article{7cb57ed5-7584-4593-afa5-1e5e2faf6a64,
  abstract     = {In this report we show that Tyr568 and Tyr570 are phosphorylated in vivo in the Kit/stem cell factor receptor (Kit/SCFR) following ligand-stimulation. By mutation of Tyr568 and Tyr570 to phenylalanine residues and expression of the mutated receptors in porcine aortic endothelial (PAE) cells, we could demonstrate a loss of activation of members of the Src family of tyrosine kinases when Tyr568 was mutated, while mutation of Tyr570 only led to a minor decrease in activation of Src family members. Mutation of both tyrosine residues led to a complete loss of Src family kinase activation. Phosphorylation of the adapter protein Shc by growth factor receptors provides association sites for Grb2-Sos, thereby activating the Ras/MAP kinase pathway. A much lowered degree of Shc phosphorylation, Ras and Erk2 activation and c-fos induction was seen in the Y568F mutant, while in the Y570F mutant these responses were less affected. In contrast, the mitogenic response was only slightly reduced. In a mutant receptor with both Tyr568 and Tyr570 mutated to phenylalanine residues, no phosphorylation of Shc and no activation of Ras and Erk2 was seen in response to stem cell factor stimulation, very weak induction of c-fos was seen and the mitogenic response was severely depressed. These data show that Ras/MAP kinase activation and c-fos induction by Kit/SCFR are mediated by members of the Src family kinases. However, the mitogenic response is only to a minor extent dependent on Src kinase activity.},
  author       = {Lennartsson, Johan and Blume-Jensen, Peter and Hermanson, Monica and Pontén, Emma and Carlberg, Monica and Rönnstrand, Lars},
  issn         = {1476-5594},
  keyword      = {Vascular/drug effects/metabolism
Enzyme Activation
*Gene Expression Regulation
*Genes,*Adaptor Proteins,Signal Transducing
*Adaptor Proteins,fos
Humans
Ligands
MAP Kinase Signaling System/*physiology
Mitogen-Activated Protein Kinase 1/*metabolism
Molecular Sequence Data
Mutagenesis,Post-Translational
Proteins/*physiology
Proto-Oncogene Proteins c-kit/*physiology
Proto-Oncogene Proteins p21(ras)/*metabolism
Recombinant Fusion Proteins/metabolism/pharmacology
Shc Signaling Adaptor Proteins
Stem Cell Factor/pharmacology/physiology
Swine
src-Family Kinases/*physiology,Site-Directed
Phosphorylation
Phosphotyrosine/physiology
*Protein Processing,Vesicular Transport
Amino Acid Sequence
Amino Acid Substitution
Animals
Aorta/cytology
Cell Division/drug effects
Cells,Cultured
Endothelium},
  language     = {eng},
  number       = {40},
  pages        = {5546--5553},
  publisher    = {Nature Publishing Group},
  series       = {Oncogene},
  title        = {Phosphorylation of Shc by Src family kinases is necessary for stem cell factor receptor/c-kit mediated activation of the Ras/MAP kinase pathway and c-fos induction},
  volume       = {18},
  year         = {1999},
}