Transport of cell adhesion molecules: How does Rab21 organise integrin trafficking on a mechanistic level?

细胞粘附分子的运输：Rab21 如何在机制水平上组织整合素运输？

• 批准号: 242476905
• 负责人: Professor Dr. Martin Aepfelbacher, since 2/2017
• 金额: --
• 依托单位: Abteilung Schiffbau und Meerestechnik, Nautik, Biologie, Bionik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/242476905?language=en
• 关键词: Transport; cell; adhesion; molecules; How

Numerous diseases such as cancer progression, inflammation and degenerative disorders are results of deregulated cell adhesion and migration. The integrin family of transmembrane cell surface receptors have a decisive impact on the migratory and invasive capacities of cancer and immune cells. Furthermore, a variety of pathogens use integrins to invade host cells for infection, extending the relevance of integrins to infectious diseases. It is becoming increasingly evident that not only activation/deactivation, but also the endo-/exocytic cycle of integrins plays an important role in mediating integrin function. The small Ras-family GTP-binding protein Rab21, which binds to the cytoplasmic tail of alpha-integrins, is a major regulator in the endocytic trafficking of integrins. However, on a molecular or structural level the mode of action remains poorly understood mainly due to the lack of known Rab21-interacting proteins.The aim of the proposed research is to gain insights how Rab21 organises integrin trafficking on a structural-mechanistic level. To answer this question, three projects will be implemented.A) Identification of Rab21 effector proteins involved in integrin trafficking.Novel Rab21 downstream effector proteins will be identified using a quantitative mass spectrometry-based protein-protein interaction screen and tested regarding their influence on integrin trafficking.B) Structural analysis of the Rab21-integrin trafficking network. After their identification, Rab21 downstream effectors as well as the cytoplasmic tail of alpha-integrins will be crystallised in complexes with Rab21 to obtain a structural snapshot of the Rab21-regulated integrin trafficking network. The X-ray structures will provide insights into the function of the trafficking complex and answer the question how Rab21 manages to transport cargo (integrin) and bind effector proteins in parallel.C) Functional analysis of the Rab21 effector proteins. I will investigate the biochemical and cell biological function of the identified effector proteins and address the question how these effector proteins effect the dynamics of integrin endocytosis. Different microscopy techniques (confocal microscopy, live cell imaging, TIRF) will be employed.In this proposed research, I will employ a multidisciplinary approach starting with a biochemical screen and combining various state of the art and cutting edge cell and structural biological tools to maximise our mechanistic understanding of the question how integrins are trafficking from the plasma membrane to endosomes and how this trafficking influences different disease processes.

许多疾病，如癌症进展、炎症和退行性疾病，都是细胞粘附和迁移失调的结果。跨膜细胞表面受体的整合素家族对癌症和免疫细胞的迁移和侵袭能力具有决定性影响。此外，多种病原体利用整合素侵入宿主细胞进行感染，扩大了整合素与传染病的相关性。越来越明显的是，不仅整合素的激活/失活，而且整合素的内/胞吐循环在介导整合素功能中发挥着重要作用。小型 Ras 家族 GTP 结合蛋白 Rab21 与 α 整合素的细胞质尾部结合，是整合素内吞运输的主要调节因子。然而，在分子或结构水平上，人们对作用模式仍然知之甚少，这主要是由于缺乏已知的 Rab21 相互作用蛋白。本研究的目的是深入了解 Rab21 如何在结构机制水平上组织整合素运输。为了回答这个问题，将实施三个项目。A) 鉴定参与整合素运输的 Rab21 效应蛋白。将使用基于定量质谱的蛋白质-蛋白质相互作用筛选来鉴定新型 Rab21 下游效应蛋白，并测试它们对整合素运输的影响。B) Rab21 整合素运输网络的结构分析。鉴定后，Rab21下游效应子以及α-整合素的细胞质尾部将与Rab21形成复合物结晶，以获得Rab21调节的整合素运输网络的结构快照。 X 射线结构将提供对运输复合物功能的深入了解，并回答 Rab21 如何设法并行运输货物（整合素）并结合效应蛋白的问题。C) Rab21 效应蛋白的功能分析。我将研究已识别的效应蛋白的生化和细胞生物学功能，并解决这些效应蛋白如何影响整合素内吞作用的动力学的问题。将采用不同的显微镜技术（共聚焦显微镜、活细胞成像、TIRF）。在这项拟议的研究中，我将采用多学科方法，从生化筛选开始，结合各种最先进的技术和尖端细胞和结构生物学工具，以最大限度地提高我们对整合素如何从质膜运输到内体以及这种运输如何影响不同疾病过程的问题的机械理解。