BIOCHEMICAL STUDIES OF STAT NUCLEAR LOCALIZATION

STAT核定位的生物化学研究

• 批准号: 6778053
• 负责人: XIAOMIN CHEN
• 金额: $ 28.34万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6778053
• 关键词: JAK kinase; X ray crystallography; analytical ultracentrifugation; biological signal transduction; biophysics; calorimetry; cell biology; cell nucleus; dimer; fluorescence microscopy; gel filtration chromatography; genetic manipulation; genetic transcription; light scattering; phosphorylation; posttranslational modifications; protein localization; protein protein interaction; protein structure; protein structure function; protein transport; tissue /cell culture; transcription factor; transport proteins

DESCRIPTION (provided by applicant): The broad and long-term objectives of the research program are to uncover the molecular mechanism of Jak/STAT-mediated signal transduction and transcription activation. STATs are so named since they are signal transducers in the cytoplasm and activators of transcription in the nucleus. Upon receptor dimerization induced by ligand binding, Jak or receptor tyrosine kinases are activated and they in turn phosphorylate tyrosines on the receptors. The SH2-containing STAT molecules are recruited to the cell surface and become tyrosine phosphorylated by Jak or receptor kinases. They subsequently homo- or hetero-dimerize and translocate into the nucleus, where they bind to specific DNA targets and direct specific transcription initiation. The Jak/STAT pathway is involved in the signaling process of virtually every cytokine and growth factor. Dysregulation of this pathway leads to constitutively activated STAT proteins and the subsequent up-regulation of the genes of apoptosis inhibitors and cell cycle regulators. Constitutively activated STATs have been linked to numerous cancer cell lines and solid tumors including leukemia and breast cancer. Thus they have become important targets for cancer drug discovery. The major focus of this research is to elucidate the molecular mechanism underlying STAT nuclear localization at atomic resolution. The specific aims of the proposed research include (1) to determine the crystal structure of an unphosphorylated full-length STAT; (2) to study the physiological significance of the observed unphosphorylated STAT dimer structure using biochemical, biophysical, and cell biological tools; and (3) to study STAT1:NPI1 interaction and its role in STAT1 nuclear localization using biochemical, structural, and cell biological tools.

描述（由申请人提供）： 该研究计划的广泛和长期目标是揭示 Jak/STAT 介导的信号转导和转录激活的分子机制。 STAT 之所以如此命名，是因为它们是细胞质中的信号转导器和细胞核中的转录激活剂。当配体结合诱导受体二聚化时，Jak 或受体酪氨酸激酶被激活，它们反过来磷酸化受体上的酪氨酸。含有 SH2 的 STAT 分子被募集到细胞表面并被 Jak 或受体激酶磷酸化。随后它们同源或异源二聚化并易位到细胞核中，在那里它们与特定的 DNA 靶标结合并指导特定的转录起始。 Jak/STAT 通路参与几乎所有细胞因子和生长因子的信号传导过程。该途径的失调会导致 STAT 蛋白持续激活，并随后导致细胞凋亡抑制剂和细胞周期调节因子的基因上调。组成型激活的 STAT 与许多癌细胞系和实体瘤（包括白血病和乳腺癌）有关。因此它们已成为癌症药物发现的重要靶点。本研究的主要重点是阐明原子分辨率下 STAT 核定位的分子机制。本研究的具体目标包括（1）确定非磷酸化全长 STAT 的晶体结构； (2) 利用生化、生物物理和细胞生物学工具研究观察到的非磷酸化STAT二聚体结构的生理意义； (3) 使用生化、结构和细胞生物学工具研究 STAT1:NPI1 相互作用及其在 STAT1 核定位中的作用。