The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Masato Okada - One of the best experts on this subject based on the ideXlab platform.
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Light-induced Tyrosine Phosphorylation of BIT in the rat suprachiasmatic nucleus.
Journal of neurochemistry, 2002Co-Authors: Yasukazu Nakahata, Nobuaki Okumura, Masato Okada, Takaki Shima, Katsuya NagaiAbstract:Circadian changes of protein Tyrosine Phosphorylation in the hypothalamic suprachiasmatic nucleus have been studied using rats maintained under 12-h light/ 12-h dark cycles as well as constant dark conditions. We found that Tyrosine Phosphorylation of BIT (brain immunoglobulin-like molecule with Tyrosine-based activation motifs), a transmembrane glycoprotein of 90-95 kDa, was higher in the light period than in the dark period and was increased after light exposure in the dark period. Similar changes in Tyrosine Phosphorylation were observed under constant dark conditions, but its amplitude was weaker than that in 12-h light/12-h dark cycles. As the Tyrosine-phosphorylated form of BIT is able to bind to the Src homology 2 domain of a protein Tyrosine phosphatase, SHP-2, we examined association of these proteins in suprachiasmatic nucleus extracts and found that SHP-2 was coprecipitated with BIT in parallel with its Tyrosine Phosphorylation. These results suggest that Tyrosine Phosphorylation of BIT might be involved in light-induced entrainment of the circadian clock.
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Depolarization-Induced Tyrosine Phosphorylation of p130cas
Journal of biochemistry, 1998Co-Authors: Shin Kobayashi, Nobuaki Okumura, Masato Okada, Katsuya NagaiAbstract:KCl-treatment of PC12 cells induces depolarization of the plasma membrane and Ca2+ influx into the cells. We have previously shown that KCl induced Tyrosine Phosphorylation of cellular proteins of 120, 110, 68, 44, and 42 k, and that the 68 k protein was paxillin. In the present study, we found that the 120 k protein was a Crk-associated Src substrate, p130(cas). KCl-induced Tyrosine Phosphorylation of p130(cas) was not observed in EGTA-containing medium, suggesting that it was due to Ca2+ influx into the cells. Time course experiments showed that Tyrosine Phosphorylation of p130(cas) peaked at 5 min after stimulation and returned to the basal level at 60 min, while mobility shift of p130(cas) was observed within 2 min and lasted over 60 min, indicating that serine or threonine residues, in addition to Tyrosine, were phosphorylated on KCl stimulation. In vitro kinase assay of immunoprecipitates with anti-p130(cas) antibody suggested that some protein-Tyrosine kinases were associated with p130(cas). Using the substrate region of p130(cas) as the substrate, we found that Fyn and Src were activated on stimulation with KCl. These results indicate that Tyrosine Phosphorylation of p130(cas) may be involved in Ca2+-dependent events in neuronal and neuroendocrine cells.
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Depolarization-induced Tyrosine Phosphorylation of Paxillin in PC12h Cells
European journal of biochemistry, 1996Co-Authors: Muhammad Ashraf Khan, Nobuaki Okumura, Masato OkadaAbstract:Treatment of PC12h cells with a high concentration of KCl induces depolarization of the plasma membrane and Ca2+ influx into the cells. We have previously shown that KCl induced Tyrosine Phosphorylation of cellular proteins of 120, 110, 68, 44 and 42 kDa. In the present study, we found that the 68-kDa protein is paxillin, a Tyrosine kinase substrate associated with the actin cyloskeleton. A calcium ionophore, A23187, also induced Tyrosine Phosphorylation of the 68-kDa protein, while KCl did not in the presence of EGTA or nifedipine, indicating that the effect of KCl was due to the Ca2+ influx into the cells. Tyrosine Phosphorylation of paxillin was also induced by nerve growth factor and epidermal growth factor, but its migration patterns on an SDS/polyacrylamide gel were different, that is, nerve growth factor and epidermal growth factor caused upward shifts of the bands, while KCl did not. However, both forms could associate with Csk and Crk. The effect of KCl was blocked by cytochalasin D, indicating that Tyrosine Phosphorylation required the integrity of actin filaments. These results suggest that Tyrosine Phosphorylation of paxillin may be involved in Ca2+ -dependent events in neuronal and neuroendocrine cells.
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Depolarization-induced Tyrosine Phosphorylation in PC12h cells.
Journal of biochemistry, 1994Co-Authors: Nobuaki Okumura, Masato Okada, Hachiro NakagawaAbstract:Depolarization induced by KCl was found to induce Tyrosine Phosphorylation of cellular proteins in PC12h cells. By Western blotting with anti-phosphoTyrosine antibody, we detected Tyrosine Phosphorylation of proteins with molecular weights of 120, 110, 105, 95, 75, 70, 66, 44, and 42 kDa in response to KCl. The immunoprecipitates from KCl-treated cells with the antibody contained large amounts of Tyrosine-phosphorylated proteins and increased activity of Tyrosine kinase. Incubation of the immunoprecipitates with [gamma-32P]ATP resulted in Tyrosine Phosphorylation of two proteins with the molecular weights of 120 and 140 kDa. These effects were completely abolished by the addition of EGTA before KCl treatment, suggesting that the depolarization-induced Tyrosine Phosphorylation may require calcium entry into the cells from the medium. Increased activity of Tyrosine kinase phosphorylating the 120 and 140 kDa proteins was also recovered from cells stimulated with nerve growth factor, basic fibroblast growth factor, epidermal growth factor, and vasoactive intestinal peptide. Among them, depolarization by KCl elicited the strongest effect. These results indicate that a protein Tyrosine kinase that phosphorylate the 120 and 140 kDa proteins is phosphorylated or activated in response to calcium ion, cAMP, and growth factors acting through Tyrosine kinase receptors.
Nobuaki Okumura - One of the best experts on this subject based on the ideXlab platform.
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Light-induced Tyrosine Phosphorylation of BIT in the rat suprachiasmatic nucleus.
Journal of neurochemistry, 2002Co-Authors: Yasukazu Nakahata, Nobuaki Okumura, Masato Okada, Takaki Shima, Katsuya NagaiAbstract:Circadian changes of protein Tyrosine Phosphorylation in the hypothalamic suprachiasmatic nucleus have been studied using rats maintained under 12-h light/ 12-h dark cycles as well as constant dark conditions. We found that Tyrosine Phosphorylation of BIT (brain immunoglobulin-like molecule with Tyrosine-based activation motifs), a transmembrane glycoprotein of 90-95 kDa, was higher in the light period than in the dark period and was increased after light exposure in the dark period. Similar changes in Tyrosine Phosphorylation were observed under constant dark conditions, but its amplitude was weaker than that in 12-h light/12-h dark cycles. As the Tyrosine-phosphorylated form of BIT is able to bind to the Src homology 2 domain of a protein Tyrosine phosphatase, SHP-2, we examined association of these proteins in suprachiasmatic nucleus extracts and found that SHP-2 was coprecipitated with BIT in parallel with its Tyrosine Phosphorylation. These results suggest that Tyrosine Phosphorylation of BIT might be involved in light-induced entrainment of the circadian clock.
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Depolarization-Induced Tyrosine Phosphorylation of p130cas
Journal of biochemistry, 1998Co-Authors: Shin Kobayashi, Nobuaki Okumura, Masato Okada, Katsuya NagaiAbstract:KCl-treatment of PC12 cells induces depolarization of the plasma membrane and Ca2+ influx into the cells. We have previously shown that KCl induced Tyrosine Phosphorylation of cellular proteins of 120, 110, 68, 44, and 42 k, and that the 68 k protein was paxillin. In the present study, we found that the 120 k protein was a Crk-associated Src substrate, p130(cas). KCl-induced Tyrosine Phosphorylation of p130(cas) was not observed in EGTA-containing medium, suggesting that it was due to Ca2+ influx into the cells. Time course experiments showed that Tyrosine Phosphorylation of p130(cas) peaked at 5 min after stimulation and returned to the basal level at 60 min, while mobility shift of p130(cas) was observed within 2 min and lasted over 60 min, indicating that serine or threonine residues, in addition to Tyrosine, were phosphorylated on KCl stimulation. In vitro kinase assay of immunoprecipitates with anti-p130(cas) antibody suggested that some protein-Tyrosine kinases were associated with p130(cas). Using the substrate region of p130(cas) as the substrate, we found that Fyn and Src were activated on stimulation with KCl. These results indicate that Tyrosine Phosphorylation of p130(cas) may be involved in Ca2+-dependent events in neuronal and neuroendocrine cells.
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Depolarization-induced Tyrosine Phosphorylation of Paxillin in PC12h Cells
European journal of biochemistry, 1996Co-Authors: Muhammad Ashraf Khan, Nobuaki Okumura, Masato OkadaAbstract:Treatment of PC12h cells with a high concentration of KCl induces depolarization of the plasma membrane and Ca2+ influx into the cells. We have previously shown that KCl induced Tyrosine Phosphorylation of cellular proteins of 120, 110, 68, 44 and 42 kDa. In the present study, we found that the 68-kDa protein is paxillin, a Tyrosine kinase substrate associated with the actin cyloskeleton. A calcium ionophore, A23187, also induced Tyrosine Phosphorylation of the 68-kDa protein, while KCl did not in the presence of EGTA or nifedipine, indicating that the effect of KCl was due to the Ca2+ influx into the cells. Tyrosine Phosphorylation of paxillin was also induced by nerve growth factor and epidermal growth factor, but its migration patterns on an SDS/polyacrylamide gel were different, that is, nerve growth factor and epidermal growth factor caused upward shifts of the bands, while KCl did not. However, both forms could associate with Csk and Crk. The effect of KCl was blocked by cytochalasin D, indicating that Tyrosine Phosphorylation required the integrity of actin filaments. These results suggest that Tyrosine Phosphorylation of paxillin may be involved in Ca2+ -dependent events in neuronal and neuroendocrine cells.
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Depolarization-induced Tyrosine Phosphorylation in PC12h cells.
Journal of biochemistry, 1994Co-Authors: Nobuaki Okumura, Masato Okada, Hachiro NakagawaAbstract:Depolarization induced by KCl was found to induce Tyrosine Phosphorylation of cellular proteins in PC12h cells. By Western blotting with anti-phosphoTyrosine antibody, we detected Tyrosine Phosphorylation of proteins with molecular weights of 120, 110, 105, 95, 75, 70, 66, 44, and 42 kDa in response to KCl. The immunoprecipitates from KCl-treated cells with the antibody contained large amounts of Tyrosine-phosphorylated proteins and increased activity of Tyrosine kinase. Incubation of the immunoprecipitates with [gamma-32P]ATP resulted in Tyrosine Phosphorylation of two proteins with the molecular weights of 120 and 140 kDa. These effects were completely abolished by the addition of EGTA before KCl treatment, suggesting that the depolarization-induced Tyrosine Phosphorylation may require calcium entry into the cells from the medium. Increased activity of Tyrosine kinase phosphorylating the 120 and 140 kDa proteins was also recovered from cells stimulated with nerve growth factor, basic fibroblast growth factor, epidermal growth factor, and vasoactive intestinal peptide. Among them, depolarization by KCl elicited the strongest effect. These results indicate that a protein Tyrosine kinase that phosphorylate the 120 and 140 kDa proteins is phosphorylated or activated in response to calcium ion, cAMP, and growth factors acting through Tyrosine kinase receptors.
Pablo E Visconti - One of the best experts on this subject based on the ideXlab platform.
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identification of proteins undergoing Tyrosine Phosphorylation during mouse sperm capacitation
The International Journal of Developmental Biology, 2008Co-Authors: Enid Arcelay, Ana M Salicioni, Eva Wertheimer, Pablo E ViscontiAbstract:Mammalian sperm are not able to fertilize immediately upon ejaculation; they become fertilization-competent after undergoing changes in the female reproductive tract collectively termed capacitation. Although it has been established that capacitation is associated with an increase in Tyrosine Phosphorylation, little is known about the role of this event in sperm function. In this work we used a combination of two dimensional gel electrophoresis and mass spectrometry to identify proteins that undergo Tyrosine Phosphorylation during capacitation. Some of the identified proteins are the mouse orthologues of human sperm proteins known to undergo Tyrosine Phosphorylation. Among them we identified VDAC, tubulin, PDH E1 beta chain, glutathione S-transferase, NADH dehydrogenase (ubiquinone) Fe-S protein 6, acrosin binding protein precursor (sp32), proteasome subunit alpha type 6b and cytochrome b-c1 complex. In addition to previously described proteins, we identified two testis-specific aldolases as substrates for Tyrosine Phosphorylation. Genomic and EST analyses suggest that these aldolases are retroposons expressed exclusively in the testis, as has been reported elsewhere. Because of the importance of glycolysis for sperm function, we hypothesize that Tyrosine Phosphorylation of these proteins can play a role in the regulation of glycolysis during capacitation. However, neither the Km nor the Vmax of aldolase changed as a function of capacitation when its enzymatic activity was assayed in vitro, suggesting other levels of regulation for aldolase function.
Ana M. Martínez - One of the best experts on this subject based on the ideXlab platform.
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PAF-stimulated protein Tyrosine Phosphorylation in hippocampus: involvement of NO synthase.
Neurochemical research, 2002Co-Authors: M.carmen Calcerrada, R.edgardo Catalán, Ana M. MartínezAbstract:The effect of platelet-activating factor (PAF) on protein Tyrosine Phosphorylation was studied in rat hippocampal slices. PAF caused an increase in the Tyrosine Phosphorylation of two phosphoproteins, which we identified by immunoprecipitation assays as the focal adhesion kinase p125FAK and crk-associated substrate p130Cas. The PAF effect was time- and dose-dependent. In addition, the involvement of PAF receptor was demonstrated by using PCA-4248, a specific receptor antagonist. When NO synthase was inhibited by NG-monomethyl-L-arginine (L-NMA), PAF-stimulated protein Tyrosine Phosphorylation was inhibited. In conclusion, our results indicate that PAF increased the Tyrosine Phosphorylation of both p125FAK and p130Cas proteins by the production of NO in hippocampus, suggesting that PAF may play a role in the functioning of this cerebral area.
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Platelet-activating factor stimulation of p125FAK and p130Cas Tyrosine Phosphorylation in brain
Brain research, 1999Co-Authors: M.carmen Calcerrada, R.edgardo Catalán, Maria Jose Perez-alvarez, B.g. Miguel, Ana M. MartínezAbstract:Abstract The effect of platelet-activating factor (PAF) on protein Tyrosine Phosphorylation was studied in rat brain slices. PAF induced a time- and concentration-dependent increase in Tyrosine Phosphorylation of a doublet of approximately 125 kDa. These proteins were identified by immunoprecipitation as p125 FAK and p130 Cas , using monoclonal antibodies. This effect was mediated by PAF receptors, as shown by its inhibition by the action of a PAF antagonist. The Tyrosine Phosphorylation evoked by PAF was dependent, at least in part, on external calcium. The involvement of protein kinase C was demonstrated by the synergistic effect of TPA on PAF-stimulated Tyrosine Phosphorylation. The finding that PAF stimulates Tyrosine Phosphorylation of both focal adhesion protein p125 FAK and p130 Cas suggests that PAF might modulate the integrin mediated signal transduction in the brain.
Joan S. Brugge - One of the best experts on this subject based on the ideXlab platform.
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Protein Tyrosine Phosphorylation in Platelets
Advances in Molecular and Cell Biology, 2008Co-Authors: Joan S. Brugge, Edwin A. Clark, Sanford J. ShattilAbstract:Publisher Summary This chapter discusses the protein Tyrosine Phosphorylation in platelets. Activation of platelets by diverse platelet agonists causes platelet aggregation and secretion and is associated with a rapid induction of Tyrosine Phosphorylation of multiple proteins. The Phosphorylation of these proteins occurs in several temporal phases and is mediated by distinct receptor-activated signal transduction pathways. “Early” Phosphorylation events occur within seconds after agonist stimulation and are independent of fibrinogen binding to its integrin receptor, α IIb β3. Fibrinogen binding to α IIb β3 stimulates another wave of Tyrosine Phosphorylation. Finally, platelet aggregation mediated by fibrinogen cross-linking of stirred platelets induces Tyrosine Phosphorylation of still another set of proteins. Multiple Tyrosine protein kinases appear to be involved in the Phosphorylation of these proteins, and cytoskeletal interactions with appear to play an important role in coupling protein Tyrosine kinases with α IIb β3. This evidence, together with the ability of protein Tyrosine kinase inhibitors to block critical steps in agonist-induced aggregation and secretion, has implicated protein Tyrosine Phosphorylation as a possible regulatory mechanism during platelet activation. Studies have clearly demonstrated both a role for integrin receptors in the regulation of Tyrosine Phosphorylation and the utility of platelets in examining intracellular signal transduction events that are regulated by integrin family receptors. The challenge that now faces investigators in this area is to identify the substrates that are phosphorylated on Tyrosine and to establish the role of these substrates in platelet signal transduction.
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Tyrosine Phosphorylation in platelets Potential roles in intracellular signal transduction.
Trends in cardiovascular medicine, 1993Co-Authors: Edwin A. Clark, Joan S. BruggeAbstract:Tyrosine Phosphorylation has been shown to play a critical role in the induction of cellular responses to extracellular stimuli in a wide variety of cell types. In platelets, many diverse agonists induce multiple waves of Tyrosine Phosphorylation, suggesting a potential role for these protein modifications throughout the platelet activation process. Tyrosine Phosphorylation of several platelet proteins is regulated by fibrinogen binding to its integrin receptor and subsequent platelet aggregation, suggesting specific functions for Tyrosine Phosphorylation in integrin-regulated intracellular processes. In this article, we review the regulation of Tyrosine Phosphorylation and the role of Tyrosine Phosphorylation in platelet activation events.
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Protein Tyrosine Phosphorylation and the adhesive functions of platelets.
Current opinion in cell biology, 1991Co-Authors: Sanford J. Shattil, Joan S. BruggeAbstract:Abstract The intracellular signalling pathways that mediate changes in cell behavior induced by extracellular matrix and cell adhesion molecules are poorly understood. Studies on the regulation of Tyrosine Phosphorylation in platelets indicate that cell-to-cell aggregation mediated by fibrinogen binding to its integrin-family receptor, GP Ilb-Illa, and events regulated by the putative adhesion receptor, GP IV (CD36), involve Tyrosine Phosphorylation. Thus, Tyrosine Phosphorylation is implicated in cellular events crucial for hemostasis. It may also be involved in signaling mediated by integrin receptors in other cell types.
