RUI: MCB: the effect of stretch on giant cytoskeletal protein structure/function

细胞生活在一个充满运动和物理压力的世界中，因此它们必须有机制来应对这些压力。 细胞骨架是细胞用来感知拉伸并对拉伸做出反应的一个平台。 这种由多种不同蛋白质组成的网络赋予了细胞形状，但其构建方式允许灵活性和运动。 本研究主要探讨细胞骨架蛋白obscurin在牵张反应和识别中的作用。 暗蛋白的作用就像一条系绳，将细胞中遥远的部分相互连接起来。 由于它的形状，obscurin具有膨胀和收缩的能力。 有两种可能性可以解释obscurin是如何移动的。 Obscurin可以表现得像一根绳子，只有在被显著拉长时才能抵抗拉伸，或者obscurin可以表现得像一根弹簧，在被拉伸时抵抗不断增加的力。 Obscurin还可以传播生化信号，并且有间接证据表明这种功能可以通过拉伸来激活。 PI将测试obscurin功能的两个方面-拉伸反应和信号传导。 总之，这些研究将深入了解细胞如何被动和主动地对身体拉伸做出反应。这项工作将主要由本科生进行，以努力培养下一代科学家。 这里积累的数据将被纳入一个免费教育网站，在那里，其他无法获得重要研究支持的人也可以学习如何进行此类研究的技术技能。 此外，PI将为本科生开发科学伦理课程。具体而言，研究者将使用细胞和体外模型研究obscurin如何对物理拉伸反应。 Obscurin由多个独立的域组成。 许多这些个别领域已被广泛的特点。 在目标1中，PI将描述这些域在两个或三个组中的作用。 使用蛋白质NMR技术，将测量相邻结构域之间的串扰。 小角X射线散射（SAXS）提供了obscurin整体形状的动态模型。 这些实验方法将通过计算机模拟来补充，以测试这些多域系统如何响应拉伸。 总之，这些实验将详细说明obscurin如何抵抗力。 在目标二中，PI将测试当细胞被拉伸时，obscurin对整个细胞的影响。 将拉伸具有和不具有obscurin的细胞，并分析obscurin在这些条件下存在的生化后果。 总之，这两个目标将有助于定义obscurin作为拉伸电阻器的行为，并将回答obscurin是否是机械传感器的问题。

Cells live in a world full of motion and physical strain, and therefore they must have mechanisms to react to these stresses. One platform cells use to sense and respond to stretch is the cytoskeleton. This meshwork of multiple different proteins gives a cell its shape, yet is constructed in a way that allows flexibility and motion. This research is focused on the role that the cytoskeletal protein obscurin plays in stretch response and recognition. Obscurin acts like a tether, connecting far-away segments of the cell to each other. Due to its shape, obscurin has the capacity to expand and contract. There are two possibilities of how obscurin could move like this. Obscurin could behave like a rope, and only resist stretch when significantly elongated, or obscurin could behave like a spring, and resist an ever-increasing amount of force as it is stretched. Obscurin also can propagate biochemical signals, and there is circumstantial evidence that this function could be activated by stretch. The PI will test both facets of obscurin function - stretch response and signaling. Together, these studies will provide insight into how cells passively and actively respond to physical stretch. This work will be conducted primarily by undergraduate students, in an effort to train the next generation of scientists. The data accrued here will be incorporated into a free education website, where others who do not have access to significant research support can also learn the technical skills of how to do this kind of research. Additionally, the PI will develop a scientific ethics curriculum for undergraduates. Specifically, the investigator will study how obscurin reacts to physical stretch using both cellular and in vitro models. Obscurin is composed of multiple stand-alone domains. Many of these individual domains have been characterized extensively. In Aim 1, the PI will characterize how these domains act in groups of two or three. Using protein NMR techniques, the cross-talk between neighboring domains will be measured. Small angle X-ray scattering (SAXS) provide a dynamic model of obscurin's overall shape. These experimental approaches will be complimented through computer simulations to test how these multi-domain systems respond to stretch. Together, these experiments will detail how obscurin resists force. In Aim two, the PI will test what effect obscurin has on the whole cell when the cell is stretched. Cells with and without obscurin will be stretched, and the biochemical consequences of obscurin's presence in these conditions will be analyzed. Together, these two aims will help define how obscurin behaves as a stretch resistor, and will answer the question of whether or not obscurin is a mechanosensor.