scholarly journals Biochemical analysis of torso and D-raf during Drosophila embryogenesis: implications for terminal signal transduction

1993 ◽  
Vol 13 (2) ◽  
pp. 1163-1172
Author(s):  
F Sprenger ◽  
M M Trosclair ◽  
D K Morrison

Determination of anterior and posterior terminal structures of Drosophila embryos requires activation of two genes encoding putative protein kinases, torso and D-raf. In this study, we demonstrate that Torso has intrinsic tyrosine kinase activity and show that it is transiently tyrosine phosphorylated (activated) at syncytial blastoderm stages. Torso proteins causing a gain-of-function phenotype are constitutively tyrosine phosphorylated, while Torso proteins causing a loss-of-function phenotype lack tyrosine kinase activity. The D-raf gene product, which is required for Torso function, is identified as a 90-kDa protein with intrinsic serine/threonine kinase activity. D-Raf is expressed throughout embryogenesis; however, the phosphorylation state of the protein changes during development. In wild-type embryos, D-Raf is hyperphosphorylated at 1 to 2 h after egg laying, and thereafter only the most highly phosphorylated form is detected. Embryos lacking Torso activity, however, show significant reductions in D-Raf protein expression rather than major alterations in the protein's phosphorylation state. This report provides the first biochemical analysis of the terminal signal transduction pathway in Drosophila embryos.

1993 ◽  
Vol 13 (2) ◽  
pp. 1163-1172 ◽  
Author(s):  
F Sprenger ◽  
M M Trosclair ◽  
D K Morrison

Determination of anterior and posterior terminal structures of Drosophila embryos requires activation of two genes encoding putative protein kinases, torso and D-raf. In this study, we demonstrate that Torso has intrinsic tyrosine kinase activity and show that it is transiently tyrosine phosphorylated (activated) at syncytial blastoderm stages. Torso proteins causing a gain-of-function phenotype are constitutively tyrosine phosphorylated, while Torso proteins causing a loss-of-function phenotype lack tyrosine kinase activity. The D-raf gene product, which is required for Torso function, is identified as a 90-kDa protein with intrinsic serine/threonine kinase activity. D-Raf is expressed throughout embryogenesis; however, the phosphorylation state of the protein changes during development. In wild-type embryos, D-Raf is hyperphosphorylated at 1 to 2 h after egg laying, and thereafter only the most highly phosphorylated form is detected. Embryos lacking Torso activity, however, show significant reductions in D-Raf protein expression rather than major alterations in the protein's phosphorylation state. This report provides the first biochemical analysis of the terminal signal transduction pathway in Drosophila embryos.


1988 ◽  
Vol 8 (2) ◽  
pp. 843-853
Author(s):  
M J Henkemeyer ◽  
R L Bennett ◽  
F B Gertler ◽  
F M Hoffmann

We report our molecular characterization of the Drosophila melanogaster Abelson gene (abl), a gene in which recessive loss-of-function mutations result in lethality at the pupal stage of development. This essential gene consists of 10 exons extending over 26 kilobase pairs of genomic DNA. The DNA sequence encodes a protein of 1,520 amino acids with strong sequence similarity to the human c-abl proto-oncogene beginning in the type lb 5' exon and extending through the region essential for tyrosine kinase activity. When the tyrosine kinase homologous region was expressed in Escherichia coli, phosphorylation of proteins on tyrosine residues was observed with an antiphosphotyrosine antibody. These results show that the abl gene is highly conserved through evolution and encodes a functional tyrosine protein kinase required for Drosophila development.


1994 ◽  
Vol 14 (1) ◽  
pp. 735-743 ◽  
Author(s):  
S K Muthuswamy ◽  
P M Siegel ◽  
D L Dankort ◽  
M A Webster ◽  
W J Muller

Amplification and overexpression of the neu (c-erbB2) proto-oncogene has been implicated in the pathogenesis of 20 to 30% of human breast cancers. Although the activation of Neu receptor tyrosine kinase appears to be a pivotal step during mammary tumorigenesis, the mechanism by which Neu signals cell proliferation is unclear. Molecules bearing a domain shared by the c-Src proto-oncogene (Src homology 2) are thought to be involved in signal transduction from activated receptor tyrosine kinases such as Neu. To test whether c-Src was implicated in Neu-mediated signal transduction, we measured the activity of the c-Src tyrosine kinase in tissue extracts from either mammary tumors or adjacent mammary epithelium derived from transgenic mice expressing a mouse mammary tumor virus promoter/enhancer/unactivated neu fusion gene. The Neu-induced mammary tumors possessed six- to eightfold-higher c-Src kinase activity than the adjacent epithelium. The increase in c-Src tyrosine kinase activity was not due to an increase in the levels of c-Src but rather was a result of the elevation of its specific activity. Moreover, activation of c-Src was correlated with its ability to complex tyrosine-phosphorylated Neu both in vitro and in vivo. Together, these observations suggest that activation of the c-Src tyrosine kinase during mammary tumorigenesis may occur through a direct interaction with activated Neu.


1998 ◽  
Vol 334 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Hong-Hee KIM ◽  
Ulka VIJAPURKAR ◽  
Nathan J. HELLYER ◽  
Dolores BRAVO ◽  
John G. KOLAND

The role of protein tyrosine kinase activity in ErbB3-mediated signal transduction was investigated. ErbB3 was phosphorylated in vivo in response to either heregulin (HRG) in cells expressing both ErbB3 and ErbB2, or epidermal growth factor (EGF) in cells expressing both ErbB3 and EGF receptor. A recombinant receptor protein (ErbB3-K/M, in which K/M stands for Lys → Met amino acid substitution) containing an inactivating mutation in the putative ATP-binding site was also phosphorylated in response to HRG and EGF. Both the wild-type ErbB3 and mutant ErbB3-K/M proteins transduced signals to phosphatidylinositol 3-kinase, Shc and mitogen-activated protein kinases. Separate kinase-inactivating mutations in the EGF receptor and ErbB2 proteins abolished ErbB3 phosphorylation and signal transduction activated by EGF and HRG respectively. Hence the protein tyrosine kinase activity necessary for growth factor signalling via the ErbB3 protein seems to be provided by coexpressed EGF and ErbB2 receptor proteins.


Blood ◽  
1990 ◽  
Vol 76 (4) ◽  
pp. 706-715 ◽  
Author(s):  
Y Kanakura ◽  
B Druker ◽  
SA Cannistra ◽  
Y Furukawa ◽  
Y Torimoto ◽  
...  

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) exert multiple effects on the proliferation, differentiation, and function of myeloid lineage cells through their interaction with specific cell-surface receptors. There is a considerable degree of overlap in the biological effects of these two growth factors, but little is known about the mechanisms of postreceptor signal transduction. We have investigated the effects of GM-CSF and IL-3 on protein tyrosine-kinase activity in a human cell line, MO7E, which proliferates in response to either factor. Tyrosine- kinase activity was detected using immunoblotting with a monoclonal antibody (MoAb) specific for phosphotyrosine. GM-CSF and IL-3 were found to induce a nearly identical pattern of protein tyrosine phosphorylation using both one- and two-dimensional gel electrophoresis. Tyrosine phosphorylation of two cytosolic proteins in particular was increased more than 10-fold, a 93-Kd protein (pp93) and a 70-Kd protein (pp70). Tyrosine phosphorylation of pp93 and pp70 was observed within 1 minute, reached a maximum at 5 to 15 minutes, and gradually decreased thereafter. Other proteins of 150, 125, 63, 55, 42, and 36 Kd were also phosphorylated on tyrosine in response to both GM- CSF and IL-3, although to a lesser degree. Tyrosine phosphorylation was dependent on the concentration of GM-CSF over the range of 0.1 to 10 ng/mL and on IL-3 over the range of 1 to 30 ng/mL. Stimulation of MO7E cells with 12–0-tetradecanoyl-phorbol-13-acetate (TPA) or cytokines such as G-CSF, M-CSF, interleukin-1 (IL-1), interleukin-4 (IL-4), interleukin-6 (IL-6), interferon gamma, tumor necrosis factor (TNF), or transforming growth factor-beta (TGF-beta) did not induce tyrosine phosphorylation of pp93 or pp70, suggesting that these two phosphoproteins are specific for GM-CSF-or IL-3-induced activation. The extent and duration of phosphorylation of all the substrates were increased by pretreatment of cells with vanadate, an inhibitor of protein-tyrosine phosphatases. Importantly, culture of MO7E cells with vanadate (up to 10 mumol/L) resulted in a dose-dependent increase in GM- CSF-or IL-3-induced proliferation of up to 1.8-fold. These results suggest that tyrosine phosphorylation may be important for GM-CSF and IL-3 receptor-mediated signal transduction and that cell proliferation may be, at least partially, regulated by a balance between CSF-induced protein-tyrosine kinase activity and protein-tyrosine phosphatase activity.


Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3457-3461 ◽  
Author(s):  
T Matsuda ◽  
T Hirano

Hematopoietic cytokines, including interleukin-3 (IL-3), IL-6, and granulocyte colony-stimulating factor (G-CSF), induce the proliferation, differentiation, and activation of hematopoietic lineage cells. These cytokines activate the Jak/Stat-mediated signal transduction pathway that is important in the biologic activities of these cytokines. In this study, we showed that hematopoietic cytokines, such as IL-3, IL-6, and G-CSF, all induced tyrosine-phosphorylation of Stat family proteins and Stat-associated 150-kD and 72-kD molecules in hematopoietic lineage cell lines. Furthermore, we showed that the 72-kD molecule had tyrosine kinase activity. The tyrosine kinase activity of the 72-kD molecule was enhanced by the stimulation through an IL-6 signal transducer, gp130, that was shared among the receptors for the IL-6-related cytokine subfamily, such as leukemia inhibitory factor, oncostatin M, IL-11, and ciliary neurotrophic factor. Because 72-kD tyrosine kinase was distinct from Syk, Tec, and Btk and coimmunoprecipitated with anti-Stat antiserum, we termed it Stat- associated 72-kD tyrosine kinase (p72sak). p72sak may directly activate Stat family proteins or other signal transducing molecules for IL-3, G- CSF, and the IL-6-related cytokine subfamily.


Blood ◽  
1990 ◽  
Vol 76 (4) ◽  
pp. 706-715 ◽  
Author(s):  
Y Kanakura ◽  
B Druker ◽  
SA Cannistra ◽  
Y Furukawa ◽  
Y Torimoto ◽  
...  

Abstract Human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) exert multiple effects on the proliferation, differentiation, and function of myeloid lineage cells through their interaction with specific cell-surface receptors. There is a considerable degree of overlap in the biological effects of these two growth factors, but little is known about the mechanisms of postreceptor signal transduction. We have investigated the effects of GM-CSF and IL-3 on protein tyrosine-kinase activity in a human cell line, MO7E, which proliferates in response to either factor. Tyrosine- kinase activity was detected using immunoblotting with a monoclonal antibody (MoAb) specific for phosphotyrosine. GM-CSF and IL-3 were found to induce a nearly identical pattern of protein tyrosine phosphorylation using both one- and two-dimensional gel electrophoresis. Tyrosine phosphorylation of two cytosolic proteins in particular was increased more than 10-fold, a 93-Kd protein (pp93) and a 70-Kd protein (pp70). Tyrosine phosphorylation of pp93 and pp70 was observed within 1 minute, reached a maximum at 5 to 15 minutes, and gradually decreased thereafter. Other proteins of 150, 125, 63, 55, 42, and 36 Kd were also phosphorylated on tyrosine in response to both GM- CSF and IL-3, although to a lesser degree. Tyrosine phosphorylation was dependent on the concentration of GM-CSF over the range of 0.1 to 10 ng/mL and on IL-3 over the range of 1 to 30 ng/mL. Stimulation of MO7E cells with 12–0-tetradecanoyl-phorbol-13-acetate (TPA) or cytokines such as G-CSF, M-CSF, interleukin-1 (IL-1), interleukin-4 (IL-4), interleukin-6 (IL-6), interferon gamma, tumor necrosis factor (TNF), or transforming growth factor-beta (TGF-beta) did not induce tyrosine phosphorylation of pp93 or pp70, suggesting that these two phosphoproteins are specific for GM-CSF-or IL-3-induced activation. The extent and duration of phosphorylation of all the substrates were increased by pretreatment of cells with vanadate, an inhibitor of protein-tyrosine phosphatases. Importantly, culture of MO7E cells with vanadate (up to 10 mumol/L) resulted in a dose-dependent increase in GM- CSF-or IL-3-induced proliferation of up to 1.8-fold. These results suggest that tyrosine phosphorylation may be important for GM-CSF and IL-3 receptor-mediated signal transduction and that cell proliferation may be, at least partially, regulated by a balance between CSF-induced protein-tyrosine kinase activity and protein-tyrosine phosphatase activity.


Cell ◽  
1990 ◽  
Vol 61 (2) ◽  
pp. 203-212 ◽  
Author(s):  
Axel Ullrich ◽  
Joseph Schlessinger

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3457-3461 ◽  
Author(s):  
T Matsuda ◽  
T Hirano

Abstract Hematopoietic cytokines, including interleukin-3 (IL-3), IL-6, and granulocyte colony-stimulating factor (G-CSF), induce the proliferation, differentiation, and activation of hematopoietic lineage cells. These cytokines activate the Jak/Stat-mediated signal transduction pathway that is important in the biologic activities of these cytokines. In this study, we showed that hematopoietic cytokines, such as IL-3, IL-6, and G-CSF, all induced tyrosine-phosphorylation of Stat family proteins and Stat-associated 150-kD and 72-kD molecules in hematopoietic lineage cell lines. Furthermore, we showed that the 72-kD molecule had tyrosine kinase activity. The tyrosine kinase activity of the 72-kD molecule was enhanced by the stimulation through an IL-6 signal transducer, gp130, that was shared among the receptors for the IL-6-related cytokine subfamily, such as leukemia inhibitory factor, oncostatin M, IL-11, and ciliary neurotrophic factor. Because 72-kD tyrosine kinase was distinct from Syk, Tec, and Btk and coimmunoprecipitated with anti-Stat antiserum, we termed it Stat- associated 72-kD tyrosine kinase (p72sak). p72sak may directly activate Stat family proteins or other signal transducing molecules for IL-3, G- CSF, and the IL-6-related cytokine subfamily.


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