i3S-Institute for Research and Innovation in Health, University of Porto, Rua Alfredo Allen 208, 4200-135, Porto, Portugal.
IBMC-Institute for Molecular and Cell Biology, University of Porto, Rua Alfredo Allen 208, 4200-135, Porto, Portugal.
Nat Commun. 2024 Nov 9;15(1):9720. doi: 10.1038/s41467-024-54155-8.
Post-translational cycles of α-tubulin detyrosination and tyrosination generate microtubule diversity, the cellular functions of which remain largely unknown. Here we show that α-tubulin detyrosination regulates kinetochore-microtubule attachments to ensure normal chromosome oscillations and timely anaphase onset during mitosis. Remarkably, detyrosinated α-tubulin levels near kinetochore microtubule plus-ends depend on the direction of chromosome motion during metaphase. Proteomic analyses unveil that the KNL-1/MIS12/NDC80 (KMN) network that forms the core microtubule-binding site at kinetochores and the microtubule-rescue protein CLASP2 are enriched on tyrosinated and detyrosinated microtubules during mitosis, respectively. α-tubulin detyrosination enhances CLASP2 binding and NDC80 complex diffusion along the microtubule lattice in vitro. Rescue experiments overexpressing NDC80, including variants with slower microtubule diffusion, suggest a functional interplay with α-tubulin detyrosination for the establishment of a labile kinetochore-microtubule interface. These results offer a mechanistic explanation for how different detyrosinated α-tubulin levels near kinetochore microtubule plus-ends fine-tune load-bearing attachments to both growing and shrinking microtubules.
α-微管蛋白去酪氨酸化和酪氨酸化的翻译后循环产生微管多样性，其细胞功能在很大程度上尚不清楚。在这里，我们表明α-微管蛋白去酪氨酸化调节着动粒微管的附着，以确保有丝分裂过程中染色体的正常振荡和适时的后期起始。值得注意的是，动粒微管末端附近去酪氨酸化α-微管蛋白的水平取决于有丝分裂中期染色体运动的方向。蛋白质组学分析揭示了 KNL-1/MIS12/NDC80（KMN）网络在动粒处形成微管结合的核心位点，以及微管救援蛋白 CLASP2，分别在有丝分裂过程中在酪氨酸化和去酪氨酸化微管上富集。α-微管蛋白去酪氨酸化增强了 CLASP2 的结合和 NDC80 复合物在微管晶格中的扩散。过表达 NDC80 的挽救实验，包括扩散速度较慢的变体，表明与α-微管蛋白去酪氨酸化之间存在功能相互作用，以建立不稳定的动粒微管界面。这些结果为不同的动粒微管末端附近的去酪氨酸化α-微管蛋白水平如何微调对生长和收缩微管的承载附着提供了一种机制解释。
