Tyrosine Phosphorylation of the Proto-oncogene Product Vav and Its Association with the Adapter Grb2/Ash in a Human Leukemia Cell Line UT-7 |
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| Authors: | Yutaka Hanazono Ko Sasaki Hideharu Odai Toshihide Mimura Kinuko Mitani Yoshio Yazaki Hisamaru Hirai |
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| Affiliation: | Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Hongo 7–3–1, Bunkyo-ku, Tokyo 113 |
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| Abstract: | The vav proto-oncogene product (Vav) is expressed exclusively in hematopoietic cells and is reported to have guanine nucleotide exchange activity. Here we report that granulocyte-macrophage colonystimulating factor, interleukin-3, and erythropoietin induce tyrosine phosphorylation of Vav in a human leukemia cell line UT-7. Tyrosine phosphorylation of Vav is rapid and transient; it occurs within 1 min of the stimulation and at physiological concentrations of the factors. Furthermore, we show that Vav is constitutively associated with the adapter molecule Grb2/Ash in UT-7. These data suggest that tryosine kinases, the adapter Grb2/Ash, and the guanine nucleotide exchange factor Vav are members of a signaling pathway leading to Ras activation in hematopoietic cells. |
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| Keywords: | Vav Grb2/Ash Hematopoietic growth factor Tyrosine phosphorylation Signal transduction |
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