title: Ras is not required for the interleukin 3-induced proliferation of a mouse pro-B cell line, BaF3.
abstract: It has been demonstrated that Ras is involved in interleukin 3 (IL-3)-stimulated signal transduction in various hematopoietic cultured cells (Satoh, T., Nakafuku, M., Miyajima, A., and Kaziro, Y. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 3314-3318; Duronio, V., Welham, M. J., Abraham, S., Dryden, P., and Schrader, J. W. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 1587-1591). However, it has not been fully understood which of IL-3-promoted cellular responses, i.e. proliferation, survival, and differentiation, requires Ras function. We employed a system of inducible expression of the dominant-negative (S17N) or dominant-active (G12V) mutant of Ras in BaF3 mouse pro-B cell line to analyze the role of Ras in IL-3-stimulated signal transduction. Induction of the dominant-negative Ras(S17N) effectively inhibited the IL-3-induced activation of c-Raf-1 and mitogen-activated protein kinase (MAPK). Furthermore, the activation of fos gene promoter following IL-3 stimulation was almost completely abolished when Ras(S17N) was induced. Under these conditions, Ras(S17N) exhibited no inhibitory effect on IL-3-dependent proliferation assessed by the increase of cell numbers and a mitochondrial enzyme activity. The results indicate that Ras-dependent pathways, including the Raf/MAPK/Fos pathway, are dispensable for IL-3-induced growth stimulation. When BaF3 cells were treated with a tyrosine kinase inhibitor, herbimycin A, IL-3-dependent proliferation of the cells was impaired, suggesting that tyrosine kinase-mediated pathways are critical for growth promotion. On the other hand, apoptotic cell death caused by deprivation of IL-3 was prevented by the induction of the activated mutant Ras(G12V), although the rate of cell number increase was markedly reduced. Thus, it is likely that Ras-independent pathways play important roles to facilitate the proliferation although they may not be essential for IL-3-stimulated antiapoptotic signal transduction.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes; D016227:Benzoquinones; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016762:Genes, fos; D011905:Genes, ras; D006150:Guanine Nucleotides / Q000378:metabolism; D006801:Humans; D007106:Immune Sera; D007377:Interleukin-3 / Q000494:pharmacology*; D047029:Lactams, Macrocyclic; D048728:MAP Kinase Kinase Kinase 1; D051379:Mice; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D011809:Quinones / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction; D014162:Transfection; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D006150:Guanine Nucleotides; D007106:Immune Sera; D007377:Interleukin-3; D047029:Lactams, Macrocyclic; D011518:Proto-Oncogene Proteins; D011809:Quinones; D011993:Recombinant Fusion Proteins; D017828:Rifabutin; C020754:herbimycin; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; C482578:Map3k1 protein, mouse; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins