Microtubules are crucial in cells and are regulated by various mechanisms like posttranslational modifications, microtubule-associated proteins, and tubulin isoforms. Recently, the conformation of the microtubule lattice has also emerged as a potential regulatory factor, but it has remained unclear to what extent different lattices co-exist within the cell. Using cryo-electron tomography, we find that, while most microtubules have a compacted lattice (∼41 Å monomer spacing), approximately a quarter of the microtubules displayed more expanded lattice spacings. The addition of the microtubule-stabilizing agent Taxol increased the lattice spacing of all microtubules, consistent with results on reconstituted microtubules. Furthermore, correlative cryo-light and electron microscopy revealed that the stable subset of microtubules labeled by StableMARK, a marker for stable microtubules, predominantly displayed a more expanded lattice spacing (∼41.9 Å), further suggesting a close connection between lattice expansion and microtubule stability. The coexistence of different lattices and their correlation with stability implicate lattice spacing as an important factor in establishing specific microtubule subsets.

中文翻译：

---

细胞中 StableMARK 修饰的微管具有膨胀的晶格。


微管在细胞中至关重要，并受翻译后修饰、微管相关蛋白和微管蛋白亚型等各种机制的调节。最近，微管晶格的构象也成为一种潜在的调节因素，但目前尚不清楚不同晶格在细胞内共存的程度。使用冷冻电子断层扫描，我们发现，虽然大多数微管具有紧凑的晶格（∼41 Å 单体间距），但大约四分之一的微管显示出更扩大的晶格间距。微管稳定剂紫杉醇的添加增加了所有微管的晶格间距，与重组微管的结果一致。此外，相关的冷冻光学和电子显微镜显示，由 StableMARK（稳定微管的标志物）标记的稳定微管亚群主要表现出更扩大的晶格间距 （∼41.9 Å），进一步表明晶格膨胀与微管稳定性之间存在密切联系。不同晶格的共存及其与稳定性的相关性意味着晶格间距是建立特定微管子集的重要因素。