Role of the Sec61 Translocon in EGF Receptor Trafficking and Signaling

Sec61 易位子在 EGF 受体运输和信号转导中的作用

• 批准号: 8016008
• 负责人: GRAHAM F CARPENTER
• 金额: $ 30.9万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8016008
• 关键词: Address; Antibodies; Binding; Biochemistry; Biological; Biology; Cell Cycle Progression; Cell Nucleus; Cells; Cellular biology; Clinical; Cyclin D1; Cytoplasm; Cytosol; Data; Dependence; EGF gene; Endoplasmic Reticulum; Endosomes; Epidermal Growth Factor Receptor; Erbitux; Golgi Apparatus; Grant; Growth; Growth Factor; Health; Heat-Shock Proteins 70; Hormones; Investigation; Ligands; Malignant Neoplasms; Monoclonal Antibody C225; Nuclear; Nuclear Localization Signal; Nuclear Receptors; Nuclear Translocation; Pathway interactions; Pharmaceutical Preparations; Proliferating; Proteins; Reagent; Receptor Activation; Role; Route; Signal Transduction; Sorting - Cell Movement; Testing; Transmembrane Domain; Tyrosine; cancer therapy; clinically relevant; factor C; mutant; p97 ATPase; prevent; protein misfolding; receptor; research study; response; trafficking

DESCRIPTION (provided by applicant): This application seeks to explore a new route of intracellular trafficking of growth factor-activated EGF receptor to the nucleus. Also, the capacity of a clinically relevant EGF receptor antibody to promote nuclear localization of the EGF receptor will be investigated. In brief, preliminary data show that following the addition of EGF, EGF receptors are slowly trafficked to the endoplasmic reticulum (ER). In the ER these receptors interact with the Sec61 translocon and are retrotranslocated to the cytoplasm as non-membrane bound molecules. HSP70 is required for retrotranslocation to the cytosol and likely functions by associating with transmembrane domains of the soluble EGF receptor to prevent aggregation. Knockdown of Sec61? prevents the EGF-dependent translocation of its receptor to the nucleus and the expression of cyclin D1, indicating that ER translocation is a precursor for nuclear localization and signaling function of the EGF receptor. In the first two aims, mechanistic questions are addressed regarding the cell biology and biochemistry of this pathway. In the last two aims, the pathway is explored in terms of growth control and a clinically used antibody to the EGF receptor. The first aim proposes to investigate the intracellular trafficking route by which the activated EGFR is trafficked to the ER. Experiments are proposed to determine how different cell internalization mechanisms, the Golgi, and endosomes may participate in this pathway. The second aim focuses on the mechanism by which the receptor is recognized by the Sec61 translocon in the ER. This will test the possibility that the activated receptor is recognized by the known mechanism in the ER that sorts misfolded proteins for Sec-61-dependent retrotranslocation and cytosolic degradation. Also, this aim will include experiments to identify cytoplasmic and ER factors that participate in retrotranslocation, the fate(s) of translocated receptor, and the identity of EGF receptor fragments found in the ER and nucleus. This includes HSP70 and p97, an ATPase that is tyrosine phosphorylated following the addition of EGF. The third aim will determine the possible role of Sec61 in the EGF-stimulated G1?S transition. The final aim will explore the mechanism by which the clinically employed EGF receptor antibody C225 (Erbitux) is able to induce receptor trafficking to the ER and nucleus. The role of Sec61 in cell responses to C225 will be investigated also.

描述（由申请人提供）：本申请寻求探索生长因子激活的EGF受体向细胞核的细胞内运输的新途径。此外，将研究临床相关的EGF受体抗体促进EGF受体的核定位的能力。简单地说，初步数据显示，加入EGF后，EGF受体缓慢地被运输到内质网（ER）。在ER中，这些受体与Sec 61易位子相互作用，并作为非膜结合分子逆易位至细胞质。HSP 70是向胞质溶胶的逆转位所必需的，并且可能通过与可溶性EGF受体的跨膜结构域结合来防止聚集。打倒Sec 61？阻止EGF依赖性受体向细胞核的移位和细胞周期蛋白D1的表达，表明ER移位是EGF受体核定位和信号传导功能的前体。在前两个目标中，解决了关于该途径的细胞生物学和生物化学的机械问题。在最后两个目标中，该途径在生长控制和临床使用的EGF受体抗体方面进行了探索。 第一个目的是研究活化的EGFR被贩运到ER的细胞内贩运途径。实验提出，以确定如何不同的细胞内化机制，高尔基体和内体可能参与这一途径。第二个目标集中于受体被ER中的Sec 61易位子识别的机制。这将测试激活的受体被ER中的已知机制识别的可能性，该机制将错误折叠的蛋白质分类为Sec-61依赖性逆转位和胞质降解。此外，这一目标将包括实验，以确定参与retrotranslocation细胞质和ER因子，易位受体的命运，并在ER和细胞核中发现的EGF受体片段的身份。这包括HSP 70和p97，一种在加入EGF后酪氨酸磷酸化的ATP酶。 第三个目标将确定Sec 61在EGF刺激的G1？S过渡。最后的目的将探讨临床使用的EGF受体抗体C225（爱必妥）能够诱导受体运输到ER和细胞核的机制。Sec 61在细胞对C225的反应中的作用也将被研究。