Vinculin: a key to deciphering mechanotransduction

细胞有触觉，这项研究计划旨在发现允许细胞对机械力做出反应的潜在分子机制。例如，随着肌肉的扩张并能够以更大的力量收缩，至关重要的是肌肉末端与肌腱/肌腱基质的连接也变得更加牢固。我们知道这是通过一种机械敏感的附着机械实现的，但我们还不知道这种机械是如何工作的。因此，我们将研究重点放在一种名为vinculin的蛋白质上，我们认为它将通过提供揭示潜在机制的钥匙，提供机械转导的“罗塞塔石头”。这是因为纽蛋白具有特殊的性质，当细胞内的不同位置受到收缩力量的拉动时，这些位置会变得集中。这些部位包括细胞附着到其他细胞或细胞周围的支架上的地方，细胞外基质。当这些粘连部位受到作用力时，纽蛋白被招募到这些粘连部位有助于加强它们，但目前还不知道纽蛋白是如何做到这一点的。纽蛋白以“关闭”的状态存在，在这种状态下它紧紧地卷曲在一起；在“打开”的状态下，它可以与其他蛋白质结合。事实上，与从细胞中移除纽蛋白相比，处于开启状态的纽蛋白过多会给细胞带来更多问题，但我们仍然不明白为什么会这样。因此，我们的目标是发现：1)纽球蛋白是如何被招募的对力量的反应。2)纽球蛋白是如何发挥作用的，以及哪些其他蛋白质可能提供类似的功能，从而使去除纽球蛋白的耐受性出奇地好。3)太多的纽球蛋白是如何给有机体带来问题的。我们的发现将以多种方式影响人类健康。一些人类疾病是由于细胞粘附力的减弱而引起的，这可以通过开发方法来模拟力信号来改善，从而加强粘附力。同样，癌细胞的运动或转移会使癌症更难治疗，而粘附力的增强将抑制细胞的运动。此外，了解机械转导的分子细节可能会导致新的纳米机器的设计，这种机器可以通过局部药物输送对力做出反应。虽然我们的目标是了解机械转导是如何在人类身上发挥作用的，但我们可以通过利用模式生物黑腹果蝇的实验优势来最有效地回答这些问题。在果蝇中也发现了与纽蛋白功能相关的蛋白质，我们可以利用果蝇复杂的分子遗传学，结合最先进的显微镜技术，使用纽蛋白来发现细胞如何感知和响应机械力。

Cells have a sense of touch, and this research proposal aims to discover the underlying molecular machinery that allows cells to respond to mechanical forces. For example, as muscles enlarge and are able to contract with greater force, it is critical that the attachments of the ends of the muscles to the tendon/tendon matrix also become strengthened. We know that this is achieved by a mechanosensitive attachment machinery, but we dont yet know how this machinery works. We therefore have focused our research on a protein, vinculin, that we think will provide the "Rosetta Stone" of mechanotransduction, by providing a key that will reveal the underlying mechanisms. This is because vinculin has the exceptional property of becoming concentrated at different sites within the cell, when these sites are being pulled on by contractile forces. These sites includes the places where cells attach to other cells or to the scaffolding that surrounds cells, the extracellular matrix. The recruitment of vinculin to these sites of adhesion when they are under force helps to strengthen them, but it is not known how vinculin does that. Vinculin exists in an "off" state, where it is tightly curled up, and an uncurled "on" state where it can bind to other proteins. Having too much vinculin in the on state in fact causes more problems to the cell than if vinculin is removed from the cell, but again we dont yet understand why this is the case. Our goal is therefore to discover:1) how vinculin is recruited in response to force.2) how vinculin functions, and what other proteins may be providing a similar function, such that the removal of vinculin can be tolerated surprisingly well.3) how having too much "on" vinculin causes problems to the organism.Our discoveries will impact on human health in multiple ways. Some human diseases result from the weakening of cell adhesion, which could be improved by developing methods to mimic the force signal, thus strengthening adhesion. Similarly, movement of cancer cells, or metastasis, renders cancers much more difficult to treat, and strengthening adhesion will restrain cell movement. Furthermore, understanding the molecular details of mechanotransduction may lead to the design of new nanomachines that can respond to force with local drug delivery. While our goal is to understand how mechanotransduction works in humans, we can answer these questions most effectively by using the experimental advantages of the model organism Drosophila melanogaster, the fruit fly. The proteins involved with vinculin function are also found in Drosophila, and we can use the sophisticated molecular genetics of Drosophila, combined with state of the art microscopy to use vinculin to discover how cells sense and respond to mechanical force.