Expression of tau protein in non-neuronal cells: microtubule binding and stabilization.
Expression of tau protein in non-neuronal cells: microtubule binding and stabilization.
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发表时间：
1992-06
影响因子：
4
通讯作者：
Gloria Lee;Susan L. Rook
中科院分区：
文献类型：
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作者：
Gloria Lee;Susan L. Rook
微管相关蛋白tau是一个发育调节的神经元磷蛋白家族，促进微管的组装和稳定。该蛋白质的羧基末端的一半含有三个不完全重复序列的拷贝;该区域已被发现在体外结合微管。此外，在成人特异性形式的tau蛋白中发现了重复序列的第四个拷贝。为了研究tau蛋白在体内的结构和功能，我们在组织培养细胞中瞬时表达了胎儿和成人形式的tau蛋白和tau蛋白片段。生物化学分析揭示了在细胞中合成的具有翻译后修饰异质性的全长产物。转染细胞的免疫荧光染色显示，在我们的条件下，在体内微管共定位所需的重复区域的两侧的序列。这些额外的区域可能是增强微管接触或细胞中蛋白质正确折叠所必需的。在我们的表达系统中，细胞微管的集束仅发生在使用四重复tau构建体的转染中;任何能够结合的四重复构建体也能够诱导集束。我们的数据表明，束的存在与增强的微管稳定性相关;增加稳定性的因素，如较高水平的tau蛋白表达或第四重复序列的存在，增加了显示束的转染细胞的分数。最后，细胞中tau蛋白的存在允许所有间期微管变得乙酰化，这是通常为稳定细胞微管的子集保留的翻译后修饰。
The microtubule-associated protein tau is a developmentally regulated family of neuronal phosphoproteins that promotes the assembly and stabilization of microtubules. The carboxy-terminal half of the protein contains three copies of an imperfectly repeated sequence; this region has been found to bind microtubules in vitro. In addition, a fourth copy of the repeat has been found in adult-specific forms of tau protein. To examine the structure and function of tau protein in vivo, we have transiently expressed fetal and adult forms of tau protein and tau protein fragments in tissue culture cells. Biochemical analysis reveals full-length products with heterogeneity in post-translational modification synthesized in the cells. Immunofluorescent staining of transfected cells shows that, under our conditions, sequences on both sides of the repeat region are required for in vivo microtubule co-localization. These additional regions may be required either for enhancing microtubule contacts or for proper protein folding in the cell. In our expression system, the bundling of cellular microtubules occurs only in transfections using four-repeat tau constructs; any four-repeat construct capable of binding is also able to induce bundling. Our data suggest that the presence of bundles is correlated with enhanced microtubule stability; factors that increase stability such as higher levels of tau protein expression or the presence of the fourth repeat, increase the fraction of transfected cells showing bundles. Finally, the presence of tau protein in the cell allows all interphase microtubules to become acetylated, a post-translational modification usually reserved for a subset of stable cellular microtubules.