Crosstalk between STATs and small GTPases in the control of cell division and differentiation.

STAT 和小 GTP 酶之间的串扰控制细胞分裂和分化。

• 批准号: 16209032
• 负责人: KITAMURA Toshio
• 金额: $ 31.03万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16209032/
• 关键词: nuclear transport assay; STAT3; STAT5; importin; Rac1; Cytokinesis; GAP; PhoA; インポーチン; Rac1; 細胞質分裂; GAP; RhoA; STAT; 低分子量G蛋白質; 転写; GAP蛋白質

In this research project, we have investigated cross-talk between activation of STAT3/STAT5 and Rho family small GTPases. In 2004-2005, using mouse embryonic fibroblasts where Racl can be conditionally deleted by Cre recombinase as well as a dominant negative Racl and siRNA for Racl, we demonstrated that Racl is essential for nuclear transport of STAT3 and STAT5. However, the underlying molecular mechanisms remained elusive. In 2006, we investigated how Racl controls nuclear transport of STAT3 and STAT5. To this end, we established a nuclear transport assay using permialized cells and recombinant proteins produced in F9 insect cells. The nuclear transport assay revealed that an active form of Racl, MgcRacGAP and importin a/b are required for the nuclear transport of phosphorylated STAT3 and STAT5. Interestingly, STAT/Racl/MgcRacGAP complex binds importin a only when Racl is in its GTP-bound form, indicating that MgcRacGAP plays an important role in the binding and dissociation of STAT and importins (Kawashima et al., J Cell Biol, 2006). We also found that MgcRacGAP harbors nuclear localization signal (NLS). Although STAT3 and 5 do not possess typical NLS, the present results show that MgcRacGAP and Racl works as a nuclear shaperon for the activated STAT3 and 5. In addition, we also found that MgcRacGAP also binds JAK2 that is known to phosphorylate STAT proteins. Knockdown of either MgcRacGAP or Racl not only inhibited nuclear transport of STAT3/5 but also attenuated their phosphorylation. Altogether, the present results suggested that MgcRacGAP and Racl plays critical roles in the nuclear transport of STAT3 and STAT5 as well as transport to the plasma membrane and activation of these transcription factors.

在本研究项目中，我们研究了STAT3/STAT5与Rho家族小GTPases的激活之间的串扰。在2004-2005年，我们使用小鼠胚胎成纤维细胞，其中Racl可以被Cre重组酶有条件地删除，以及Racl的显性阴性Racl和siRNA，我们证明了Racl对于STAT3和STAT5的核运输是必不可少的。然而，潜在的分子机制仍然难以捉摸。2006年，我们研究了Racl如何控制STAT3和STAT5的核转运。为此，我们建立了一种核转运实验，使用经perized处理的细胞和在F9昆虫细胞中产生的重组蛋白。核转运实验显示，磷酸化的STAT3和STAT5的核转运需要Racl、MgcRacGAP和a/b的活性形式。有趣的是，STAT/Racl/MgcRacGAP复合物仅在Racl处于gtp结合形式时才与importin a结合，这表明MgcRacGAP在STAT与importin的结合和解离中起着重要作用（Kawashima et al., J Cell Biol, 2006）。我们还发现MgcRacGAP具有核定位信号（NLS）。虽然STAT3和5不具有典型的NLS，但目前的研究结果表明，MgcRacGAP和Racl作为活化的STAT3和5的核形状子。此外，我们还发现MgcRacGAP还能结合JAK2，而JAK2已知会使STAT蛋白磷酸化。敲低MgcRacGAP或Racl不仅能抑制STAT3/5的核转运，还能减弱其磷酸化。总之，目前的结果表明，MgcRacGAP和Racl在STAT3和STAT5的核转运以及转运到质膜和激活这些转录因子中起着关键作用。

项目成果

Selective activation of STAT5 unveils its role in stem cell self-renewal of normal and leukemic hematopoiesis.

STAT5 的选择性激活揭示了其在正常和白血病造血干细胞自我更新中的作用。

• 发表时间: 2005
• 期刊: J. Exp. Med. 202
• 作者: Kato;Y;et al.
• 通讯作者: et al.

Functional analysis of an activating receptor LMIR4 as a counterpart of an inhibitory receptor LMIR3.

激活受体 LMIR4 作为抑制性受体 LMIR3 的对应物的功能分析。

• 期刊: J. Biol. Chem. (In press)
• 作者: Baba T;Mimura J;Nakamura N;Harada N;Yamamoto M;Morohashi K;Fujii-Kuriyama Y.;沖 俊彦;中島 秀明;中島 秀明;福地 由美;川島 敏行;沖俊彦;中島秀明;小埜良一;浦野敦司;箕嶋幸範;小埜良一;伊沢 久未
• 通讯作者: 伊沢 久未

Disruption of Sept6, a fusion partner gene of Mixed Lineage Leukemia (MLL), does not affect the ontogeny, leukemogenesis induced by MLL-SEPT6, or the phenotype induced by the loss of Sept4.

混合谱系白血病 (MLL) 的融合伴侣基因 Sept6 的破坏不会影响个体发育、MLL-SEPT6 诱导的白血病发生或 Sept4 缺失诱导的表型。

• 发表时间: 2005
• 期刊: Mol. Cell. Biol. 25
• 作者: Ono;R et al.
• 通讯作者: R et al.

Human placenta-derived cells have mesenchymal stem/progenitor cell potential

• DOI: 10.1634/stemcells.22-5-649
• 发表时间: 2004-01-01
• 期刊: STEM CELLS
• 影响因子: 5.2
• 作者: Fukuchi, Y;Nakajima, H;Tsuji, K
• 通讯作者: Tsuji, K

Rac1 and a GTPase-activating protein, MgcRacGAP, are required for nuclear translocation of STAT transcription factors.

• DOI: 10.1083/jcb.200604073
• 发表时间: 2006-12-18
• 期刊: JOURNAL OF CELL BIOLOGY
• 影响因子: 7.8
• 作者: Kawashima, Toshiyuki;Bao, Ying Chun;Nomura, Yasushi;Moon, Yuseok;Tonozuka, Yukio;Minoshima, Yukinori;Hatori, Tomonori;Tsuchiya, Akiho;Kiyono, Mari;Nosaka, Tetsuya;Nakajima, Hideaki;Williams, David A;Kitamura, Toshio
• 通讯作者: Kitamura, Toshio