Effects of tubulin acetylation and tubulin acetyltransferase binding on microtubule structure.
Effects of tubulin acetylation and tubulin acetyltransferase binding on microtubule structure.
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DOI：
10.1091/mbc.e13-07-0387
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发表时间：
2014-01
影响因子：
3.3
通讯作者：
Nogales E
中科院分区：
文献类型：
--
作者：
Howes SC;Alushin GM;Shida T;Nachury MV;Nogales E
α-微管蛋白的乙酰化位于微管腔内，远离大多数map。它不影响微管结构，只能影响直接与管腔结合的蛋白质。αTAT1可以与微管蛋白c端相互作用，使其易于进入管腔位点，并对其他修饰作出反应。微管蛋白经过翻译后修饰，以指定特定功能的微管亚群。这些修饰大多发生在微管蛋白的c端，并可能直接影响微管相关蛋白（MAPs）或马达的结合。Lys-40在α-微管蛋白上的乙酰化是独特的，因为它位于微管的管腔表面，远离大多数map和马达的相互作用位点。我们研究乙酰化是否改变微管的结构或微管蛋白的构象，使用低温电子显微镜（cryo-EM）。基于原丝分布或微管螺旋晶格参数，没有观察到明显的变化。此外，在最大程度去乙酰化和乙酰化微管的低温电镜重建中，没有发现微管结构的明显差异。我们的研究结果表明，乙酰化的作用必须高度定位，并影响与直接结合到微管管腔的蛋白质的相互作用。我们还研究了微管蛋白乙酰转移酶αTAT1与微管的相互作用，发现αTAT1能够与微管外部相互作用，至少部分通过微管蛋白c端相互作用。如果微管在原丝之间有侧向开口，α - tat1与微管外表面的结合可以促进α - tat1进入其腔内作用位点。
Acetylation of α-tubulin is uniquely located on the microtubule lumen and away from most MAPs. It does not affect microtubule structure and must affect only proteins that bind directly to the lumen. αTAT1 can interact with the tubulin C-termini, which could facilitate access to its luminal site and make it responsive to other modifications. Tubulin undergoes posttranslational modifications proposed to specify microtubule subpopulations for particular functions. Most of these modifications occur on the C-termini of tubulin and may directly affect the binding of microtubule-associated proteins (MAPs) or motors. Acetylation of Lys-40 on α-tubulin is unique in that it is located on the luminal surface of microtubules, away from the interaction sites of most MAPs and motors. We investigate whether acetylation alters the architecture of microtubules or the conformation of tubulin, using cryo–electron microscopy (cryo-EM). No significant changes are observed based on protofilament distributions or microtubule helical lattice parameters. Furthermore, no clear differences in tubulin structure are detected between cryo-EM reconstructions of maximally deacetylated or acetylated microtubules. Our results indicate that the effect of acetylation must be highly localized and affect interaction with proteins that bind directly to the lumen of the microtubule. We also investigate the interaction of the tubulin acetyltransferase, αTAT1, with microtubules and find that αTAT1 is able to interact with the outside of the microtubule, at least partly through the tubulin C-termini. Binding to the outside surface of the microtubule could facilitate access of αTAT1 to its luminal site of action if microtubules undergo lateral opening between protofilaments.