Carboxyterminal post-translational modifications of tubulin

Tubulins fold into compact globular domains with less structured carboxyterminal tails. These tails vary in sequence between tubulin isoforms and are exposed on the surfaces of microtubules. They can undergo a variety of posttranslational modifications, including the attachment and removal of polyglutamate chains and in the case of alpha-tunulins the loss and reattachment of a terminal tyrosine (Tyr) residue. These modifications are associated with changes in the rigidity and stability of microtubules (Song & Brady 2015; Yu et al. 2015).<br>Mutations affecting these modification processes can have severe effects on phenotype (e.g., Ikegami et al. 2007). Nevertheless, the precise molecular mechanisms by which these changes in tubulin structure modulate its functions remain unclear, so these modification processes are simply annotated here as a series of chemical transformations of tubulins.

微管蛋白折叠成紧密的球状结构域，其羧基末端尾巴结构相对松散。这些尾巴在微管蛋白同种异构体之间的序列上存在差异，并暴露于微管表面。它们可以经历多种翻译后修饰，包括多谷氨酸链的附着与移除，以及在α微管蛋白的情况下，末端酪氨酸（Tyr）残基的丢失与重新附着。这些修饰与微管刚性和稳定性的变化相关联（Song & Brady 2015；Yu 等人 2015）。影响这些修饰过程的突变可能会对表型产生严重影响（例如，Ikegami 等人 2007）。尽管如此，关于这些微管结构变化如何调节其功能的精确分子机制尚不明确，因此，这些修饰过程在此仅被注释为一系列微管蛋白的化学转化过程。