Harnessing protein unfolding and aggregation in mechanotransduction

利用力转导中的蛋白质解折叠和聚集

• 批准号: BB/S007318/1
• 负责人: Nicholas Brown
• 金额: $ 51.13万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FS007318%2F1
• 关键词: Harnessing; protein; unfolding; aggregation; mechanotransduction

Mechanical forces shape how our bodies develop and function. For instance as our muscles enlarge and contract with greater force, a mechanism senses these forces and strengthens the attachment of muscle ends to tendons so they are strong enough to withstand the increased force. This process is called mechanotransduction and it is central to many of our body's functions. The proposed research focuses on the molecular machinery involved in how cells sense these mechanical forces.All cells in the human body are held in the correct place via adhesion to neighbouring cells, and to a dense meshwork of proteins that surround cells, the extracellular matrix. Cells adhere to this matrix via cell surface proteins called integrins. Talin is the main linker protein coupling integrins to the cell's force generating machinery, engaging integrin at one end and coupling it to the cytoskeleton. As the cytoskeleton pulls on the integrin anchors, talin stretches like a spring and unfolding of talin recruits the protein vinculin, which reinforces the adhesion in a force-dependent manner. While this paradigm provides a feasible mechanism for force to induce a chemical change, namely the redistribution of vinculin within the cell, it also raises many questions, which are the focus of this research. In this proposal we build on our recent discovery of two new and unexpected pieces of the puzzle of how mechanotransduction works. We have discovered that talin unfolding can lead to self-assembly of talin molecules by a process called aggregation. This is an unexpected discovery, as protein aggregates are best known for their role in disease, for instance dementia and Alzheimer's disease are both caused by accumulation of protein aggregates. Our cells protect themselves from such aggregates using "chaperone" proteins that dissolve and refold misfolded proteins. Our central hypothesis is that these two harmful processes, protein unfolding and protein aggregation, have been harnessed by the cell to serve as elegant force sensing mechanisms that enable the cell to sense forces and convert them into biological signals. The hypothesis that we would like to test is that a normal feature of anchor sites is the formation of a meshwork of stretched talin molecules, which provide a solid platform for the assembly of many additional components required for integrin adhesion. Our pilot data suggest that the formation and rearrangement of this meshwork involves specific chaperones to control this process and to ensure it does not go wrong. We will test this hypothesis by combining the expertise of our two labs. The Goult lab will use biochemical, biophysical and structural methods to characterize how the components work together, and to identify specific changes that can be made to the molecules to alter their activity. The Brown lab will exploit the powerful genetics and imaging approaches that can be used in the fruit fly Drosophila to test the importance of the formation and remodelling of the talin meshwork in different processes that require the integrin machinery within the organism, such as attachment of muscles and anchoring of stem cells.This research is important at several levels. Our discoveries will improve our understanding of how forces strengthen cell adhesion, and how pathological protein aggregation is avoided, with potential benefits to the understanding of human disease. Diseases caused by weakening of cell adhesion may be improved by interventions that mimic the force signal and strengthen adhesion. Similarly, movement of cancer cells, or metastasis, renders cancers much more difficult to treat, and strengthening adhesion will anchor cancer cells and restrain cell movement. The experimental advantages of Drosophila will allow us to investigate the role of specific protein-protein interactions within an organism throughout its life cycle, and this knowledge will then be applied to humans.

机械力塑造了我们的身体如何发育和运作。例如，当我们的肌肉以更大的力量扩张和收缩时，一种机制会感知这些力量，并加强肌肉末端与肌腱的连接，使它们足够强大，能够承受增加的力量。这个过程被称为机械传导，它是我们身体许多功能的核心。这项研究的重点是细胞如何感知这些机械力的分子机制。人体内的所有细胞都是通过粘附到相邻细胞以及细胞周围的密集蛋白质网络（细胞外基质）而被固定在正确的位置。细胞通过称为整合素的细胞表面蛋白粘附于该基质。Talin是将整联蛋白偶联至细胞的力产生机制的主要连接蛋白，在一端接合整联蛋白并将其偶联至细胞骨架。当细胞骨架拉动整联蛋白锚时，塔林蛋白像弹簧一样伸展，塔林蛋白的展开招募了黏着斑蛋白，黏着斑蛋白以力依赖的方式加强了粘附。虽然这种范式提供了一个可行的机制，力诱导的化学变化，即在细胞内的黏着斑蛋白的重新分配，它也提出了许多问题，这是本研究的重点。在这个提议中，我们建立在我们最近发现的两个新的和意想不到的机械转导如何工作的难题。我们已经发现，塔林展开可以导致塔林分子的自组装过程称为聚集。这是一个意想不到的发现，因为蛋白质聚集体最为人所知的是它们在疾病中的作用，例如痴呆和阿尔茨海默病都是由蛋白质聚集体的积累引起的。我们的细胞利用“伴侣”蛋白来保护自己免受这种聚集体的伤害，这种蛋白质可以溶解和重新折叠错误折叠的蛋白质。我们的中心假设是，这两个有害的过程，蛋白质解折叠和蛋白质聚集，已经被细胞利用来作为优雅的力传感机制，使细胞能够感知力并将其转化为生物信号。我们想要检验的假设是，锚位点的正常特征是形成拉伸的talin分子的网状结构，这为整合素粘附所需的许多额外组分的组装提供了坚实的平台。我们的试验数据表明，这种网络的形成和重排涉及特定的伴侣来控制这一过程，并确保它不会出错。我们将结合我们两个实验室的专业知识来验证这一假设。Goult实验室将使用生物化学，生物物理和结构方法来表征组分如何协同工作，并确定可以对分子进行的特定变化以改变其活性。布朗实验室将利用强大的遗传学和成像方法，可用于果蝇，以测试在不同的过程中，需要在有机体内的整合素机制，如肌肉的附着和干细胞的锚定的塔林网络的形成和重塑的重要性。这项研究在几个层面上是重要的。我们的发现将提高我们对力如何加强细胞粘附的理解，以及如何避免病理性蛋白质聚集，对人类疾病的理解具有潜在的益处。由细胞粘附减弱引起的疾病可以通过模仿力信号并加强粘附的干预来改善。类似地，癌细胞的移动或转移使得癌症更难以治疗，并且增强粘附将锚癌细胞并抑制细胞移动。果蝇的实验优势将使我们能够研究特定蛋白质-蛋白质相互作用在生物体整个生命周期中的作用，然后将这些知识应用于人类。

项目成果

Talin in mechanotransduction and mechanomemory at a glance.

• DOI: 10.1242/jcs.258749
• 发表时间: 2021-10-15
• 期刊: Journal of cell science
• 影响因子: 4
• 作者: Goult BT;Brown NH;Schwartz MA
• 通讯作者: Schwartz MA