ROLE OF MYOSINS I AND II IN CELL MOTILITY

细胞运动性在多种正常和非典型肺炎中起核心作用。 病理过程。神经系统中细胞运动的例子 包括生长锥体的移动和神经母细胞的迁移 发育中的神经胶质细胞。一个显著的例子说明了 运动性导致疾病可见于恶性胶质瘤。单元格来自 这些肿瘤从原发部位迁移到相当远的地方， 有时从一个大脑半球跨越到另一个大脑半球。它是 很可能是运动性对这些肿瘤的侵袭性和 很难治疗。 越来越多的证据表明，两种细胞骨架 蛋白质--肌动蛋白和肌球蛋白--组成了驱动运动的马达。 肌球蛋白可分为两组，称为肌球蛋白I和肌球蛋白II。这些 在运动细胞的不同区域中发现了两种形式的肌球蛋白，以及 他们显然扮演着不同的角色。这些不同的功能必须 反映在酶学、结构和机制上的差异 监管。 本申请中将提供的数据将显示肌球蛋白I和 II亚型存在于几种原发的中枢神经系统恶性肿瘤中，包括 神经胶质瘤。我将在这份申请中提议首先对此进行扩展 通过筛选更广泛的胶质瘤细胞系以及 以观察这两种肌球蛋白亚型是否都是 现在时。我还将研究这些物质在细胞内的分布 异构体及其对动力刺激生长因子的反应。 第二，我将分离肌球蛋白I和II，并测量 描述它们与肌动蛋白和肌动蛋白相互作用的平衡常数 三磷酸腺苷。最后，我将研究肌球蛋白I的独特结构方面 具体来说，使用了各种生化和生物物理技术。 后两个实验将使用棘阿米巴中的肌球蛋白I和II Castellanii，一种单细胞可移动的有机体，因为这种来源可以提供 足够大的蛋白质数量进行测量，我 求婚。棘阿米巴之间高度的序列同源性 肌球蛋白I和II以及它们的脊椎动物同行意味着这些 实验应该能让我对中枢神经系统和 神经胶质瘤肌球蛋白。 这些研究的结果将被用来构建详细的 肌动蛋白-肌球蛋白相互作用如何产生运动性的分子模型。 这些研究可能最终会使药理学的发展 细胞运动性的调节剂，可以改变生物 恶性胶质瘤的侵袭性。

Cell motility plays a central role in a wide variety of normal and pathological processes. Examples of cell motility in the nervous system include the movement of growth cones and the migration of neuroblasts and glial cells that occur in development. A striking example of how motility leads to disease can be seen in malignant gliomas. Cells from these tumors migrate considerable distances from the primary site, sometimes crossing from one cerebral hemisphere to the other. It is likely that motility is important in making these tumors so invasive and difficult to treat. There is a growing body of evidence that two cytoskeletal proteins--actin and myosin--compose the motor that drives motility. Myosins can be divided into two groups, called myosins I and II. These two forms of myosin are found in different regions of motile cells, and they clearly have different roles. These different functions must be reflected in differences in enzymology, structure, and mechanism of regulation. Data to be presented in this application will show that myosin I and II isoforms are present in several primary CNS malignancies, including gliomas. I will propose in this application to first expand on this observation by screening a wider variety of glioma cell lines as well as developing, embryonic brain in order to see if both myosin isoforms are present. I will also examine the intracellular distribution of these isoforms and their response to motility-stimulating growth factors. Second, I will isolate myosins I and II and measure the rate and equilibrium constants that describe their interactions with actin and ATP. Finally, I will examine the unique structural aspects of myosin I in detail, using a variety of biochemical and biophysical techniques. These latter experiments will use myosins I and II from Acanthameoba castellanii, a unicellular motile organism, as this source can provide quantities of protein large enough to perform the measurements that I propose. The high degree of sequence homology between Acanthamoeba myosins I and II and their vertebrate counterparts means that these experiments should allow me to make valid conclusions about CNS and glioma myosins. Results of these studies will be used to construct a detailed molecular model of how the actin-myosin interaction produces motility. These studies may ultimately allow the development of pharmacologic modulators of cell motility that could alter the biological aggressiveness of malignant glial tumors.