TBC1D3: A HOMINOID-SPECIFIC GENE THAT REGULATES GROWTH FACTOR RECEPTOR SIGNALING

TBC1D3：调节生长因子受体信号传导的类人猿特异性基因

• 批准号: 7937782
• 负责人: PHILIP D STAHL
• 金额: $ 31.91万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7937782
• 关键词: Basic Science; Binding; Biochemical; Biological Process; Cell Proliferation; Cells; Cellular biology; Cognition; Complex; Data; Development; Disease; Endocytosis; Epidermal Growth Factor; Epidermal Growth Factor Receptor; Event; Evolution; Family; Functional disorder; Genes; Goals; Growth Factor; Growth Factor Receptors; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Human; Human Biology; Hydrolysis; IRS1 gene; Insulin-Like Growth Factor I; Insulin-Like-Growth Factor I Receptor; Malignant neoplasm of prostate; Mediating; Modeling; Molecular; Molecular and Cellular Biology; Monomeric GTP-Binding Proteins; Motion; Oncogenes; Pathway interactions; Phosphorylation; Physiology; Process; Protein Isoforms; Proteins; Receptor Signaling; Research; Role; Serine; Signal Pathway; Signal Transduction; Somatomedins; Structure; Testing; Threonine; Tyrosine Phosphorylation Site; Work; gene function; human disease; mutant; public health relevance; receptor coupling; response; three dimensional structure; trafficking; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): The molecular cell biology of human- and hominoid-specific genes is virtually a terra incognita in basic research. Understanding the molecular cell biology of human-specific genes will open a new vista of research of wide import to understanding human biology and disease. TBC1D3 is a widely expressed hominoid-specific gene, and recent work indicates that TBC1D3 is a powerful stimulant of the EGF and IGF-1 receptor pathways. Thus, expression of TBC1D3 promotes cellular proliferation and enhances the activation of Ras in response to growth factors. TBC1D3 contains a TBC domain that interacts with the small GTPase Rab5, a key regulator of endocytosis. We speculate that TBC1D3 may be both a growth factor receptor regulator and a Rab5 effector. This proposal focuses upon defining the biochemical mechanisms that are set in motion by TBC1D3 and result in cell proliferation. In Specific Aim 1, we will carry out a structure-function study to determine domains in TBC1D3 involved in cell localization and in Ras activation. To understand the linkage between TBC1D3 and the Ras pathway, we will identify serine/threonine and tyrosine-phosphorylation sites on TBC1D3 and validate the role TBC1D3-interacting proteins, Grb2 and 14-3-3, in Ras activation. In Specific Aim 2, we will quantify the interaction between TBC1D3 and the Rab5 subfamily of GTPases. By modeling the TBC domain of TBC1D3 using 3-dimensional structures of known TBC domains, we will identify key residues at the TBC1D3:Rab5 interface and test their role in Rab5 binding. To confirm and extend these initial structural studies, the structure of the TBC domain will be solved. In Specific Aim 3, we hypothesize that TBC1D3 stimulates cell signaling/proliferation by modulating IRS1 phosphorylation and via the interaction between TBC1D3 and the E3 ubiquitin ligase Cul7. We will characterize the effect of TBC1D3 on IRS1 phosphorylation and turnover. To understand the role of Cul7 in TBC1D3 function, we will determine the domains that mediate TBC1D3-Cul7 interaction and using deletion mutants, determine the function of the TBC1D3-Cul7 complex. The cell and molecular biology of TBC1D3 may represent a model to understand the evolution of human-specific genes that function to modulate and regulate evolutionarily conserved cell signaling pathways. PUBLIC HEALTH RELEVANCE: TBC1D3 is a hominoid-specific gene that regulates growth factor receptor signaling. TBC1D3 has been shown to be an oncogene and to be over-expressed in certain proliferative disorders. Human specific genes have not been extensively studied in spite of their relevance to the human condition and their potential role in human specific diseases. This work proposes to elucidate the mechanism of action of TBC1D3 at the cellular and molecular level. TBC1D3 may serve as a model for developing an understanding of the function of human-specific genes in regulating complex signaling pathways.

描述（由申请人提供）：人类和类人猿特异性基因的分子细胞生物学实际上是基础研究中的一个未知领域。了解人类特异性基因的分子细胞生物学将为了解人类生物学和疾病开辟一个具有广泛重要性的新研究前景。 TBC1D3 是一种广泛表达的类人猿特异性基因，最近的研究表明 TBC1D3 是 EGF 和 IGF-1 受体途径的强大刺激剂。因此，TBC1D3 的表达促进细胞增殖并增强 Ras 响应生长因子的激活。 TBC1D3 包含一个 TBC 结构域，可与小 GTPase Rab5（内吞作用的关键调节因子）相互作用。我们推测TBC1D3可能既是生长因子受体调节剂又是Rab5效应器。该提案的重点是定义 TBC1D3 启动并导致细胞增殖的生化机制。在具体目标 1 中，我们将进行结构功能研究，以确定 TBC1D3 中涉及细胞定位和 Ras 激活的域。为了了解 TBC1D3 和 Ras 通路之间的联系，我们将鉴定 TBC1D3 上的丝氨酸/苏氨酸和酪氨酸磷酸化位点，并验证 TBC1D3 相互作用蛋白 Grb2 和 14-3-3 在 Ras 激活中的作用。在具体目标 2 中，我们将量化 TBC1D3 和 GTPases 的 Rab5 亚家族之间的相互作用。通过使用已知 TBC 结构域的 3 维结构对 TBC1D3 的 TBC 结构域进行建模，我们将识别 TBC1D3:Rab5 界面处的关键残基并测试它们在 Rab5 结合中的作用。为了确认和扩展这些初步的结构研究，TBC结构域的结构将得到解决。在具体目标 3 中，我们假设 TBC1D3 通过调节 IRS1 磷酸化以及 TBC1D3 与 E3 泛素连接酶 Cul7 之间的相互作用来刺激细胞信号传导/增殖。我们将描述 TBC1D3 对 IRS1 磷酸化和周转的影响。为了了解 Cul7 在 TBC1D3 功能中的作用，我们将确定介导 TBC1D3-Cul7 相互作用的结构域，并使用缺失突变体确定 TBC1D3-Cul7 复合物的功能。 TBC1D3 的细胞和分子生物学可能代表了理解人类特异性基因进化的模型，这些基因的功能是调节和调控进化上保守的细胞信号传导途径。公共健康相关性：TBC1D3 是一种类人科动物特异性基因，可调节生长因子受体信号传导。 TBC1D3 已被证明是一种癌基因，并且在某些增殖性疾病中过度表达。尽管人类特定基因与人类状况相关及其在人类特定疾病中的潜在作用，但尚未得到广泛研究。这项工作拟在细胞和分子水平上阐明 TBC1D3 的作用机制。 TBC1D3 可作为模型来了解人类特异性基因在调节复杂信号通路中的功能。