BIOPHYSICAL STUDIES OF CYTOSKELETAL FUNCTION

这项研究正在开发和应用生物物理测定， 细胞骨架功能 该项目采用三种不同的相互 互补的方法。 一种分析，认识到 细胞骨架的主要功能是维持或改变 细胞形状，使用一种新的方法来测量细胞 变形性 这提供了一个物理的量化指标， 细胞骨架的状态，用所需的力来衡量 使粘附在固体上的细胞的暴露表面略微湿润 底层 生物物理分析这种测量使用 连续介质力学理论和模型实验包括 项目的一部分。 它的目标是提取定量的 细胞粘度和弹性模量的估计值。 同时，变形能力对形状的依赖性， 细胞的生理状态和细胞骨架结构， 细胞骨架参与生理功能， 因为加帽和分泌将凭经验表征。 该项目的第二部分将这项工作进行到分子水平。 通过确定蛋白质在活细胞中的功能， 调节聚合和相互作用的程度， 微丝 蛋白质如凝溶胶蛋白和α-辅肌动蛋白， 已经在体外得到很好的表征， 进入细胞的细胞质。 细胞骨架的操作性分析 状态，包括形态，细胞粘弹性，和 细胞内转运将测量调节的 细胞骨架上的蛋白质。 该项目的第三部分扩展了荧光相关性 光谱学和荧光光漂白恢复 细胞骨架聚合反应。 前者将用于 测量聚合度的分布;后者， 以测量电池中的聚合反应动力学。 这些 方法将提供更多人不容易获得的信息。 常规技术。

This research is developing and applying biophysical assays for cytoskeletal function. The project uses three different mutually complementary approaches. One assay, recognizing that a principal function of the cytoskeleton is to maintain or change cell shape, uses a new method for measuring cellular deformability. This provides a quantitative index of the physical state of the cytoskeleton, measured in terms of the force needed slightly to indent the exposed surface of a cell adherent to a solid substratum. Biophysical analysis of this measurement using continuum mechanical theory and model experiments comprises one portion of the project. Its goal is to extract quantitative estimates for cellular viscosities and elasticity moduli. Concurrently, the dependence of deformability on the shape, physiological state and cytoskeletal structure of a cell and the participation of the cytoskeleton in physiological functions such as capping and secretion will be characterized empirically. A second portion of the project carries this work to the molecular level by determining the function in living cells of proteins which modulate the extent of polymerization and interactions in microfilaments. Proteins such as gelsolin and alpha-actinin, which have been well characterized in vitro, will be introduced into the cytoplasm of cells. An operational assay of cytoskeletal state which includes morphology, cellular viscoelasticity, and intracellular transport will gauge the effects of the modulating proteins on the cytoskeleton. A third portion of the project extends Fluorescence Correlation Spectroscopy and Fluorescence Photobleaching Recovery to cytoskeletal polymerization reactions. The former will be used to measure the distribution of degrees of polymerization; the latter, to measure polymerization reaction kinetics in cells. These methods will provide information not readily available by more conventional techniques.