The motility of axonemal dynein is regulated by the tubulin code.
The motility of axonemal dynein is regulated by the tubulin code.
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DOI：
10.1016/j.bpj.2014.10.061
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发表时间：
2014-12-16
影响因子：
3.4
通讯作者：
Howard J
中科院分区：
文献类型：
--
作者：
Alper JD;Decker F;Agana B;Howard J
微管多样性产生于不同微管蛋白基因的利用和翻译后修饰，调节许多细胞过程，包括细胞分裂、神经元分化和生长以及中心粒组装。在纤毛和鞭毛的情况下，多细胞生物学研究表明微管多样性对轴丝组装和运动很重要。然而，目前尚不清楚微管多样性是否直接影响轴丝动力蛋白的活性，即驱动轴丝跳动的马达，也不知道是否对运动性的影响是间接的，可能是通过马达上游的调节通路，如中心对、径向辐条或动力蛋白调节复合体。为了测试微管多样性是否可以直接调节轴丝动力蛋白的活性，我们询问了在体外，α-微管蛋白的主要翻译后修饰赖氨酸40(K40)的乙酰化或去乙酰化，或者α-和β-微管蛋白C-末端的蛋白水解性裂解、去酪氨酸化、聚谷氨酰化和多糖修饰的位置以及大多数遗传多样性是否会影响外臂轴突动力蛋白的活性。通过位移加权速度分析对运动进行量化，并对结果进行数学模拟，我们发现K40乙酰化增加，CTTS降低轴膜动力蛋白的运动。这些结果表明，轴丝动力蛋白直接破译微管蛋白密码，这对真核生物纤毛节拍的调节具有重要意义。
Microtubule diversity, arising from the utilization of different tubulin genes and from posttranslational modifications, regulates many cellular processes including cell division, neuronal differentiation and growth, and centriole assembly. In the case of cilia and flagella, multiple cell biological studies show that microtubule diversity is important for axonemal assembly and motility. However, it is not known whether microtubule diversity directly influences the activity of the axonemal dyneins, the motors that drive the beating of the axoneme, nor whether the effects on motility are indirect, perhaps through regulatory pathways upstream of the motors, such as the central pair, radial spokes, or dynein regulatory complex. To test whether microtubule diversity can directly regulate the activity of axonemal dyneins, we asked whether in vitro acetylation or deacetylation of lysine 40 (K40), a major posttranslational modification of α-tubulin, or whether proteolytic cleavage of the C-terminal tail (CTT) of α- and β-tubulin, the location of detyrosination, polyglutamylation, and polyglycylation modifications as well as most of the genetic diversity, can influence the activity of outer arm axonemal dynein in motility assays using purified proteins. By quantifying the motility with displacement-weighted velocity analysis and mathematically modeling the results, we found that K40 acetylation increases and CTTs decrease axonemal dynein motility. These results show that axonemal dynein directly deciphers the tubulin code, which has important implications for eukaryotic ciliary beat regulation.