Mitotic phosphorylation by NEK6 and NEK7 reduces the microtubule affinity of EML4 to promote chromosome congression
Mitotic phosphorylation by NEK6 and NEK7 reduces the microtubule affinity of EML4 to promote chromosome congression
复制标题
DOI：
10.1126/scisignal.aaw2939
复制
发表时间：
2019-08-13
影响因子：
7.3
通讯作者：
Fry, Andrew M.
中科院分区：
文献类型：
--
作者：
Adib, Rozita;Montgomery, Jessica M.;Fry, Andrew M.
EML4是一种促进微管稳定性的微管相关蛋白。我们研究了它在细胞周期中的调控，发现EML4在间期以点状分布在微管格子上，但在有丝分裂中与纺锤体微管的联系减少。微管沉积和三维重建的冷冻电子显微镜显示，EML4的碱性N末端结构域介导了它与微管表面α和β微管蛋白的酸性C末端尾巴的结合。在体外，有丝分裂酶NEK6和NEK7使EML4的丝氨酸(144)和丝氨酸(146)的N-末端结构域磷酸化，这些激酶的缺失导致有丝分裂中EML4与微管的结合增加。S144A-S146A双突变体不仅与有丝分裂微管结合不当，而且增加了微管的稳定性，干扰了染色体的聚集。此外，NEK6或NEK7的结构性激活减少了EML4与间期微管的联系。总之，这些数据支持一个模型，在该模型中，NEK6和NEK7依赖的磷酸化促进有丝分裂中EML4从微管中解离，这是有效的染色体聚集所必需的。
EML4 is a microtubule-associated protein that promotes microtubule stability. We investigated its regulation across the cell cycle and found that EML4 was distributed as punctate foci along the microtubule lattice in interphase but exhibited reduced association with spindle microtubules in mitosis. Microtubule sedimentation and cryo-electron microscopy with 3D reconstruction revealed that the basic N-terminal domain of EML4 mediated its binding to the acidic C-terminal tails of alpha- and beta-tubulin on the microtubule surface. The mitotic kinases NEK6 and NEK7 phosphorylated the EML4 N-terminal domain at Ser(144) and Ser(146) in vitro, and depletion of these kinases in cells led to increased EML4 binding to microtubules in mitosis. An S144A-S146A double mutant not only bound inappropriately to mitotic microtubules but also increased their stability and interfered with chromosome congression. In addition, constitutive activation of NEK6 or NEK7 reduced the association of EML4 with interphase microtubules. Together, these data support a model in which NEK6- and NEK7-dependent phosphorylation promotes the dissociation of EML4 from microtubules in mitosis in a manner that is required for efficient chromosome congression.