Reversal of axonal growth defects in an extraocular fibrosis model by engineering the kinesin-microtubule interface.
Reversal of axonal growth defects in an extraocular fibrosis model by engineering the kinesin-microtubule interface.
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DOI：
10.1038/ncomms10058
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发表时间：
2016-01-18
影响因子：
16.6
通讯作者：
Muto E
中科院分区：
文献类型：
--
作者：
Minoura I;Takazaki H;Ayukawa R;Saruta C;Hachikubo Y;Uchimura S;Hida T;Kamiguchi H;Shimogori T;Muto E
人β3-微管蛋白（TUBB 3）的突变导致称为先天性眼外肌纤维化3型（CFEOM 3）的眼动力障碍。在CFEOM 3中，由于受损的轴突引导和维持，眼神经系统发育异常;然而，将TUBB 3突变与轴突生长缺陷联系起来的潜在机制仍不清楚。在这里，我们研究微管（MT）为基础的运动在体外使用与重组TUBB 3形成的MT。我们发现与疾病相关的TUBB 3突变R262 H和R262 A损害了驱动蛋白运动的运动性和ATP酶活性。在驱动蛋白的L12环中工程化突变令人惊讶地恢复了携带R262 A突变的MT上的运动性和ATP酶活性的正常水平。此外，在表达相同突变的CFEOM 3小鼠模型中，过表达抑制突变驱动蛋白恢复体内轴突生长。总的来说，这些发现确立了TUBB 3-R262残基介导驱动蛋白相互作用的关键作用，而驱动蛋白相互作用又是正常轴突生长和大脑发育所必需的。 β3-微管蛋白的突变如何导致先天性眼外肌纤维化3型中轴突生长缺陷仍不清楚。Minoura等人开发了一种使用重组人微管蛋白的模型系统，其证明了微管蛋白突变、受损的驱动蛋白运动性和轴突生长缺陷之间的联系。
Mutations in human β3-tubulin (TUBB3) cause an ocular motility disorder termed congenital fibrosis of the extraocular muscles type 3 (CFEOM3). In CFEOM3, the oculomotor nervous system develops abnormally due to impaired axon guidance and maintenance; however, the underlying mechanism linking TUBB3 mutations to axonal growth defects remains unclear. Here, we investigate microtubule (MT)-based motility in vitro using MTs formed with recombinant TUBB3. We find that the disease-associated TUBB3 mutations R262H and R262A impair the motility and ATPase activity of the kinesin motor. Engineering a mutation in the L12 loop of kinesin surprisingly restores a normal level of motility and ATPase activity on MTs carrying the R262A mutation. Moreover, in a CFEOM3 mouse model expressing the same mutation, overexpressing the suppressor mutant kinesin restores axonal growth in vivo. Collectively, these findings establish the critical role of the TUBB3-R262 residue for mediating kinesin interaction, which in turn is required for normal axonal growth and brain development. How mutations in β3-tubulin cause axonal growth defects in congenital fibrosis of the extraocular muscles type 3 remains elusive. Minoura et al. develop a model system using recombinant human tubulin that demonstrates a link between tubulin mutation, impaired kinesin motility and axonal growth defects.