| Project/Area Number |
14370044
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | Kobe University |
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Principal Investigator |
YAMAMURA Hirohei Kobe University, Dept of genome sciences, Prof., 大学院・医学系研究科, 教授 (90030882)
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| Co-Investigator(Kenkyū-buntansha) |
TOHYAMA Yumi Kobe University, Dept of genome sciences, Res.Assoc., 大学院・医学系研究科, 助手 (70362770)
SADA Kiyonao Kobe University, Dept of genome sciences, Assist.Prof., 大学院・医学系研究科, 講師 (10273765)
YANAGI Shigeru Kobe University, Dept of genome sciences, Assoc.Prof., 大学院・医学系研究科, 助教授 (60252003)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 2003: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2002: ¥8,600,000 (Direct Cost: ¥8,600,000)
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| Keywords | protein-tyrosine kinase / Syk / Pak2 / Cbl / ubiquitination / 3BP2 / phagocytosis / lysosomes / チロシンキナーゼ / アダプター蛋白質 / Cbl-b / c-Cbl / CRAM / 蛋白質リン酸化反応 / 蛋白質チロシンリン酸化反応 / 非受容体型チロシンキナーゼ / 細胞接着 / 酸化ストレス / 細胞骨格 / ユビチキン・プロテアソーム |
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| Research Abstract |
1) Treatment of cells with sorbitol to induce hyperosmolarity results in the translocation of Pak2 and Syk to the region surrounding the nucleus and in dramatic enhancement of their association. Cotransfection of Pak2 and Syk leads to the activation of JNK under hyperosmotic conditions. Pak2 short interfering RNA suppresses sorbitol-mediated activation of endogenous Syk and JNK, thus identifying a novel pathway for JNK activation by Cdc42.
2) Aggregation of the high affinity IgE receptor (Fc varepsilon RI) induces the rapid ubiquitination of Lyn in rat basophilic leukaemia RBL-2H3 cells. Treatment of cells with a proteasome inhibitor enhances the ubiquitination of Lyn. Co-transfection study shows that both c-Cbl and Cbl-b could induce the ubiquitination of activated Lyn in COS cells. Over-expression of membrane-anchored form of c-Cbl inhibits the Fc varepsilon RI-mediated degranulation and cytokine gene production in RBL-2H3 cells by the down-regulation of the kinase activity of Lyn through the enhanced ubiquitination. Furthermore Cbl-b is a negative regulator of both Lyn-Syk-LAT and Gab2 mediated complementary signaling pathways in FcepsilonRI-mediated mast cell activation.
3) Using the transient expression system in COS-7 cells, 3BP2 was predominantly phosphorylated on Y174, Y183, and Y446 when it was coexpressed with Syk. An in vitro binding study revealed that phosphorylation of Y446 by Syk was likely to create a binding site for the Lyn-SH2 domain in RBL-2H3 cells. In addition, proline-rich region of 3BP2 bound to the Lyn-SH3 domain. Overexpression of 3BP2 in RBL-2H3 cells resulted in an enhancement of Lyn autophosphorylation. Thus the adaptor protein 3BP2 is a potential regulator of Lyn as a ligand of its SH3/SH2 domains in EcepsilonRI-mediated signaling in mast cells.
4) As the role of Syk related to phagocytosis, we showed that Syk is essential for the endosomal fusion to lysosomes in the crosslinking-induced-endocytosis.
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