Structural and Functional Characteristics of Tubulin Isoforms

针对微管蛋白结构表征的研究 同种型（基因产物）和同种型（翻译后变体） 将继续进行。 具体目标是：（1）， 完成神经元特异性的结构表征 III类同种型，特别注意测定 侧链的连接性的谷氨酰化;（2）、使用 串联质谱法与酶消化结合 以及特定的化学修饰来测序和表征 翻译后修饰，尤其是多聚谷氨酰化， 其它β-微管蛋白同种型的磷酸化;和（3）， 合成并确定光亲和标记的适用性 秋水仙素类的结合位点的定位 微管蛋白异源二聚体，随后进行串联质谱 修饰的微管蛋白的测序。 微管是一类极其重要的细胞 结构蛋白（细胞骨架），有助于 细胞的形态和功能特征：它们 包括鞭毛结构和功能的基础， 纤毛;他们是关键的细胞骨架元素与 染色体运动和细胞分裂的极性;它们 提供细胞内支架以维持细胞形状;以及 由于真核细胞中某些细胞内转运现象 利用微管作为沿着运输的结构轨道 发生时，它们有助于定向或空间 细胞功能和亚细胞的组织方面 动力学 这些研究的长期目标是了解 结构变化的功能意义， 存在于微管蛋白同种型和同种型中。

Research directed at structural characterization of tubulin isotypes (gene products) and isoforms (post-translational variants) will be continued. The specific objectives will be to: (1), complete the structural characterization of the neuron-specific class III isotype, with particular attention to the determination of the connectivity of the side chain glutamylation; (2), use tandem mass spectrometry in conjunction with enzymatic digestion and specific chemical modifications to sequence and characterize post-translational modification, especially polyglutamylation and phosphorylation, of other beta-tubulin isotypes; and (3), synthesize and determine the applicability of photoaffinity labels of the colchicine class for localization of the binding site on tubulin heterodimer, followed by tandem mass spectrometry sequencing of the modified tubulin. Microtubules are an extremely important class of cellular structural proteins (cytoskeleton) which contribute to the morphological and functional characteristics of the cell: they comprise the basis for structure and function of flagella and cilia; they are the key cytoskeletal elements associated with chromosomal movement and polarity of cellular divisions; they provide an intracellular scaffolding to maintain cell shape; and since certain intracellular transport phenomena in eukaryotic cells utilize microtubules as the structural track along which transport takes place, they contribute to directional or spatial organizational aspects of cellular function and subcellular dynamics. The long term goal of these studies is to understand the functional significance of the structural variations which are present in tubulin isoforms and isotypes.