MZT 蛋白在 γ-微管蛋白环复合物中形成多面结构模块。
MZT Proteins Form Multi-Faceted Structural Modules in the γ-Tubulin Ring Complex.
机构信息
Laboratory of Chemistry and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica, and National Defense Medical Center, Taipei, Taiwan; Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan.
出版信息
Cell Rep. 2020 Jun 30;31(13):107791. doi: 10.1016/j.celrep.2020.107791.
Microtubule organization depends on the γ-tubulin ring complex (γ-TuRC), a ∼2.3-MDa nucleation factor comprising an asymmetric assembly of γ-tubulin and GCP2-GCP6. However, it is currently unclear how the γ-TuRC-associated microproteins MZT1 and MZT2 contribute to the structure and regulation of the holocomplex. Here, we report cryo-EM structures of MZT1 and MZT2 in the context of the native human γ-TuRC. MZT1 forms two subcomplexes with the N-terminal α-helical domains of GCP3 or GCP6 (GCP-NHDs) within the γ-TuRC "lumenal bridge." We determine the X-ray structure of recombinant MZT1/GCP6-NHD and find it is similar to that within the native γ-TuRC. We identify two additional MZT/GCP-NHD-like subcomplexes, one of which is located on the outer face of the γ-TuRC and comprises MZT2 and GCP2-NHD in complex with a centrosomin motif 1 (CM1)-containing peptide. Our data reveal how MZT1 and MZT2 establish multi-faceted, structurally mimetic "modules" that can expand structural and regulatory interfaces in the γ-TuRC.
微管组织取决于γ-微管蛋白环复合物（γ-TuRC），这是一个~2.3MDa 的成核因子，由 γ-微管蛋白和 GCP2-GCP6 的不对称组装组成。然而，目前尚不清楚与 γ-TuRC 相关的微蛋白 MZT1 和 MZT2 如何促进全复合物的结构和调节。在这里，我们报告了 MZT1 和 MZT2 在天然人 γ-TuRC 背景下的冷冻电镜结构。MZT1 在 γ-TuRC“内腔桥”内与 GCP3 或 GCP6 的 N 端 α 螺旋结构域（GCP-NHD）形成两个亚复合物。我们确定了重组 MZT1/GCP6-NHD 的 X 射线结构，发现它与天然 γ-TuRC 中的结构相似。我们确定了另外两个 MZT/GCP-NHD 样亚复合物，其中一个位于 γ-TuRC 的外表面，由 MZT2 和与中心体素 motif 1（CM1）含有肽的 GCP2-NHD 组成。我们的数据揭示了 MZT1 和 MZT2 如何建立多方面的、结构模拟的“模块”，这些模块可以扩展 γ-TuRC 中的结构和调节界面。
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