Woodward Cora L, Mendonça Luiza M, Jensen Grant J
Division of Biology, California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA.
Cell Mol Life Sci. 2015 Sep;72(17):3401-9. doi: 10.1007/s00018-015-1898-y. Epub 2015 Apr 12.
The vault complex is the largest cellular ribonucleoprotein complex ever characterized and is present across diverse Eukarya. Despite significant information regarding the structure, composition and evolutionary conservation of the vault, little is know about the complex's actual biological function. To determine if intracellular vaults are morphologically similar to previously studied purified and recombinant vaults, we have used electron cryo-tomography to characterize the vault complexes found in the thin edges of primary human cells growing in tissue culture. Our studies confirm that intracellular vaults are similar in overall size and shape to purified and recombinant vaults previously analyzed. Results from subtomogram averaging indicate that densities within the vault lumen are not ordered, but randomly distributed. We also observe that vaults located in the extreme periphery of the cytoplasm predominately associate with granule-like structures and actin. Our ultrastructure studies augment existing biochemical, structural and genetic information on the vault, and provide important intracellular context for the ongoing efforts to understand the biological function of the native cytoplasmic vault.
穹窿复合体是迄今所鉴定出的最大的细胞核糖核蛋白复合体，存在于各种真核生物中。尽管已经有了关于穹窿结构、组成和进化保守性的大量信息，但对于该复合体的实际生物学功能却知之甚少。为了确定细胞内的穹窿在形态上是否与之前研究的纯化和重组穹窿相似，我们使用了电子冷冻断层扫描技术来表征在组织培养中生长的原代人类细胞薄边缘中发现的穹窿复合体。我们的研究证实，细胞内穹窿在总体大小和形状上与之前分析的纯化和重组穹窿相似。亚断层平均结果表明，穹窿腔内的密度不是有序排列的，而是随机分布的。我们还观察到，位于细胞质最外围的穹窿主要与颗粒状结构和肌动蛋白相关联。我们的超微结构研究丰富了关于穹窿的现有生化、结构和遗传信息，并为目前正在进行的了解天然细胞质穹窿生物学功能的努力提供了重要的细胞内背景信息。
