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: 7574580
• 负责人: GRAHAM F CARPENTER
• 金额: $ 31.85万
• 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/7574580
• 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; Heat-Shock Proteins 70; Hormones; Investigation; Ligands; Malignant Neoplasms; Membrane; 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. PUBLIC HEALTH RELEVANCE: The focus of this grant is the EGF receptor, a protein that is a rational target for several chemotherapeutic drugs that are approved for clinical use for different cancers. The application proposes investigation of this receptor in response to its normal activator, a hormone-like growth factor that stimulates cells to proliferate, as well as an antibody to the receptor that is one of the clinically approved reagents for cancer treatment.

描述（由申请人提供）：本申请旨在探索生长因子激活的EGF受体到核的细胞内运输的新途径。同样，将研究临床相关的EGF受体抗体促进EGF受体核定位置的能力。简而言之，初步数据表明，添加EGF后，EGF受体被慢慢运输到内质网（ER）。在ER中，这些受体与Sec61转运相互作用，并将其转化为细胞质作为非膜结合分子。 HSP70是通过与可溶性EGF受体的跨膜结构域关联以防止聚集的，需要向细胞质转递的逆转录和可能的功能。 Sec61的敲除？防止其受体依赖EGF依赖性易位和细胞周期蛋白D1的表达，这表明ER易位是EGF受体的核定位和信号传导功能的先驱。在前两个目的中，有关该途径的细胞生物学和生物化学的机理问题。在最后两个目的中，探索了该途径的生长控制和EGF受体的临床使用抗体。 第一个目的是调查细胞内贩运途径，该途径通过该途径被激活的EGFR贩运到ER。提出了实验以确定不同的细胞内在化机制，高尔基体和内体如何参与该途径。第二个目的侧重于ER中的Sec61转运器识别受体的机制。这将测试活化受体通过ER中已知机制识别的可能性，即ER中已知的蛋白质错误折叠的蛋白质依赖于SEC-61依赖性转向转换和胞质降解的可能性。此外，此目标将包括实验，以鉴定参与逆转录逆处的细胞质和ER因子，易位受体的命运以及在ER和核中发现的EGF受体片段的身份。这包括HSP70和P97，这是一种ATPase，在添加EGF后是酪氨酸磷酸化的。 第三个目标将确定SEC61在EGF刺激的G1转变中的可能作用。最终目的将探索临床使用的EGF受体抗体C225（Erbitux）能够诱导受体运输到ER和核的机制。还将研究SEC61在细胞对C225的反应中的作用。 公共卫生相关性：这笔赠款的重点是EGF受体，它是一种蛋白质，是几种化学治疗药物的合理靶标，这些药物被批准用于不同癌症的临床用途。该应用提出了对该受体的正常活化剂的研究，该受体是一种激素样生长因子，可刺激细胞增殖，以及对受体的抗体，这是临床批准的癌症治疗试剂之一。