Regulation and Function of Intermediate Filaments in Cell Mechanics

在这个资助项目中，我们的总体假设是，细胞骨架 IF 的组装状态和机械特性的改变，特别是由波形蛋白 (VIF) 组成的 III 型 IF，在调节细胞响应机械信号和化学信号的微机械特性方面发挥着重要作用。 这些研究至关重要，因为 IF 是哺乳动物细胞细胞骨架系统的主要元素，但它们在细胞运动中的具体功能仍然未知。 6 位项目负责人及其研究目标如下：西北大学的 R. Goldman 将确定波形蛋白 IF (VIF) 系统如何响应机械和化学信号而变化，并将纯化和表征 VIF 组装和分解时形成的波形蛋白前体。 V. Gelfand，西北大学 确定 VIF 与微管和肌动蛋白丝之间的关系，确定负责 VIF 前体易位的分子马达，并研究 VIF 如何影响细胞骨架动力学和微管 (MT) 动力学。哈佛大学的 G. Danuser 将测试以下假设：VIF 网络的形成涉及空间分布的装配线，该过程涉及分子马达，并且 VIF 网络组装调节 MT 和微丝 (MF) 的组装。哈佛大学的 D. Weitz 将确定由纯化的波形蛋白、从细胞和活细胞中分离的天然 VIF 网络制备的体外组装 VIF 网络的微机械特性。 P. Janmey，宾夕法尼亚大学， 将确定 VIF 网络如何影响活细胞的微机械特性，以及它如何响应基底刚度和外力而变化。康涅狄格大学的 P. Burkhard 将利用生物物理技术和 X 射线晶体学来确定波形蛋白二聚体的结构和生物物理性质，并研究 VIF 组装中间体的形成。在所有这些研究中，将检查不同翻译后磷酸化事件的调节功能。

In this Program Project Grant our overarching hypothesis is that alterations in the assembly states and mechanical properties of cytoskeletal IF, specifically the type III IF composed of vimentin (VIF), play important roles in regulating the micromechanical properties of cells in response to mechano- and chemosignalling. These studies are critically important as IF are major elements of the cytoskeletal system of mammalian cells and yet their specific functions in cell motility remain unknown. The 6 Project Leaders, and their research aims are as follows: R. Goldman, Northwestern University, will determine how the vimentin IF (VIF) system changes in response to mechanical and chemical signals, and will purify and characterize the vimentin precursors that form as VIF assemble and disassemble. V. Gelfand, Northwestern University will determine the relationship between VIF with microtubules and actin filaments, identify the molecular motors responsible for translocating VIF precursors, and investigate how VIF affect cytoskeletal dynamics and microtubule (MT) dynamics. G. Danuser, Harvard University, will test the hypotheses that VIF network formation involves a spatially distributed assembly line, that this process involves molecular motors, and that VIF network assembly modulates assembly of MT and microfilaments (MF). D. Weitz, Harvard University, will determine the micromechanical properties of in vitro asembled VIF networks prepared from purified vimentin, native VIF networks isolated from cells and in living cells. P. Janmey, University of Pennsylvannia, will determine how the VIF network contributes to the micromechanical properties of living cells and how this changes in response to substrate stiffness and external forces. P. Burkhard, University of Connecticut, will use biophysical techniques and X-ray crystallography to determine the structure and biophysical properties of the vimentin dimer and study the formation of VIF assembly intermediates. In all of these studies, the regulatory function of different posttranslational phosphorylation events will be examined.