MECHANISM OF SEGREGATION OF MODIFIED TUBULIN IN VIVO

这项研究的长期目标是了解目的和 细胞骨架分化的机制，即， 细胞骨架改变其在细胞事件中的作用。 特别是 微管蛋白的可逆的翻译后修饰涉及 在C末端添加或去除酪氨酸残基。 先前 实验室的研究已经确定酪氨酸化和 非酪氨酸化微管蛋白包含在不同的细胞群中， 在培养的细胞中的微管。 该项目有三个目标： (1)以确定非酪氨酸化（Glu） 微管中酪氨酸化（Tyr）微管蛋白广泛存在; (2)确定Glu和Tyr微管蛋白的分离是否 分离的微管似乎参与有丝分裂或细胞 （3）确定这两种转化的机制。 后修饰的微管蛋白变得差异分布， vivo. 将使用肽检查几种类型的培养细胞 Tyr和Glu微管蛋白特异性抗体。 参与有丝分裂的细胞 将用光学和电子显微镜免疫定位进行检查， 为了确定有丝分裂微管的群体包含哪些 α-微管蛋白的种类。 SV 40病毒在两种细胞系中的转化 将被用作细胞骨架异常的例子， 转型 在其中Tyr和Glu微管蛋白的不对称性被破坏的每种情况下， 观察到，微管的位置和任何假定的功能， 每个人都会注意到。 为了了解它的重要性， 获得观察到的Tyr差异分布的机制， Glu微管蛋白、微管在体内和裂解细胞中会解聚 模型 在几种条件下的再聚合将导致 Glu和Tyr微管蛋白的微分或等效分布。 几 Glu和Tyr微管蛋白分离成 因此可以测试单独的微管。 由于微管功能异常是癌症的组成部分 和其他疾病，试图发现他们的本地化控制， 在细胞分裂、分化和转化中的作用 明显的重要性。 （左）

The long-range goal of this research is to understand the purpose and mechanism of a cytoskeletal differentiation, that is, modifications in the cytoskeleton which alter its role in cellular events. In particular, a reversible post-translational modification of a tubulin involves the addition or removal of a tyrosine residue at the C terminus. Previous research in the laboratory has determined that tyrosinated and nontyrosinated tubulin are contained in different populations of macrotubules in cultured cells. The aims of this project are three-fold: (1) to determine whether asymmetry of distribution of nontyrosinated (Glu) and tyrosinated (Tyr) tubulins in microtubules is of widespread occurrence; (2)\to ascertain whether or not the segregation of the Glu and Tyr tubulins into separate microtubules appears to be involved in mitosis or cell transformation; and (3) to determine the mechanism by which these two post-translationally modified tubulins become differentially distributed in vivo. Several types of cultured cells will be examined using peptide antibodies specific for Tyr and for Glu tubulin. Cells engaged in mitosis will be examined with light and electron microscopic immunolocalization in order to determine which population of mitotic microtubules contain which species of alpha-tubulin. Transformation by SV40 virus in two cell lines will be used as an example of cytoskeletal abnormalities induced by transformation. In each case in which asymmetry of Tyr and Glu tubulin is observed, the location and any putative functions of microtubules containing each will be noted. To learn about the significance and the mechanism of obtaining the observed differential distribution of Tyr and Glu tubulin, microtubules will be depolymerized in vivo and in lysed cell models. Repolymerization under several conditions will result in differential or equivalent distributions of Glu and Tyr tubulin. Several possible mechanisms for the segregation of Glu and Tyr tubulins into separate microtubules can thus be tested. Since the abnormal function of microtubules is an integral part of cancer and other diseases, attempts to discover the control of their localization and function in cell division, differentiation, and transformation is of obvious importance. (L)