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: 7460439
• 负责人: GRAHAM F CARPENTER
• 金额: $ 28.67万
• 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/7460439
• 关键词: Address; Antibodies; Binding; Biochemistry; Cell Nucleus; Cells; Cellular biology; Clinical; Cyclin D1; Cytoplasm; Cytosol; Data; EGF gene; Endoplasmic Reticulum; Endosomes; Epidermal Growth Factor Receptor; Erbitux; Fc Receptor; Golgi Apparatus; Grant; Growth; Growth Factor; Heat-Shock Proteins 70; Hormones; Investigation; Malignant Neoplasms; Membrane; Monoclonal Antibody C225; Nuclear; Nuclear Localization Signal; Pathway interactions; Pharmaceutical Preparations; Proliferating; Proteins; Public Health; Reagent; Role; Route; Signal Transduction; Sorting - Cell Movement; Testing; Transmembrane Domain; Tyrosine; cancer therapy; clinically relevant; 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受体在细胞内运输至细胞核的新途径。此外，还将研究临床相关 EGF 受体抗体促进 EGF 受体核定位的能力。简而言之，初步数据表明，添加 EGF 后，EGF 受体缓慢转运至内质网 (ER)。在 ER 中，这些受体与 Sec61 易位子相互作用，并作为非膜结合分子逆向易位至细胞质。 HSP70 是逆向转位至胞质溶胶所必需的，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而发挥作用。 Sec61 的击倒？阻止其受体依赖于 EGF 的易位至细胞核以及细胞周期蛋白 D1 的表达，表明 ER 易位是 EGF 受体核定位和信号传导功能的前体。在前两个目标中，解决了有关该途径的细胞生物学和生物化学的机制问题。在最后两个目标中，从生长控制和临床使用的 EGF 受体抗体方面探索了该途径。 第一个目标是研究激活的 EGFR 被转运至 ER 的细胞内转运途径。建议进行实验来确定不同的细胞内化机制、高尔基体和内体如何参与该途径。第二个目标集中于 ER 中 Sec61 易位子识别受体的机制。这将测试激活的受体被 ER 中已知机制识别的可能性，该机制对错误折叠的蛋白质进行排序，以进行 Sec-61 依赖性逆转录易位和胞质降解。此外，该目标还包括通过实验来鉴定参与逆转位的细胞质和内质网因子、易位受体的命运以及内质网和细胞核中发现的 EGF 受体片段的身份。其中包括 HSP70 和 p97，一种在添加 EGF 后酪氨酸磷酸化的 ATP 酶。 第三个目标将确定 Sec61 在 EGF 刺激的 G1?S 转变中可能发挥的作用。最终目标是探索临床使用的EGF受体抗体C225（爱必妥）诱导受体转运至内质网和细胞核的机制。 Sec61 在细胞对 C225 反应中的作用也将被研究。 公共健康相关性：本次资助的重点是 EGF 受体，这种蛋白质是多种化疗药物的合理靶点，这些药物已被批准用于临床治疗不同的癌症。该申请建议研究该受体对其正常激活剂（一种刺激细胞增殖的激素样生长因子）以及该受体的抗体（临床批准的癌症治疗试剂之一）的反应。