The spindle pole body of Aspergillus nidulans is asymmetrical and contains changing numbers of γ-tubulin complexes
The spindle pole body of Aspergillus nidulans is asymmetrical and contains changing numbers of γ-tubulin complexes
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DOI：
10.1242/jcs.234799
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发表时间：
2019-12-15
影响因子：
4
通讯作者：
Fischer, Reinhard
中科院分区：
文献类型：
--
作者：
Gao, Xiaolei;Schmid, Marjorie;Fischer, Reinhard
中心体是动物细胞中重要的微管组织中心。此外，在许多细胞类型中发现了非中心体MTOC（ncMTOC）。它们的组成和结构知之甚少。在这里，我们分析了核MTOC（纺锤体，SPBs）和隔MTOC构巢曲霉。它们都含有γ-微管蛋白沿着γ-微管蛋白复合物蛋白（GCPs）家族成员。我们的数据表明，SPB由外斑块处的γ-微管蛋白小复合物（γ-TuSC）和内斑块处的较大的γ-微管蛋白环复合物（γ-TuRC）组成。我们发现，MztA蛋白，人类MOZART蛋白（也称为MZT 1）的直系同源物，与内部斑块受体PcpA（同源的裂变酵母Pcp 1）在SPBs相互作用，而没有相互作用，也没有共定位检测MztA和外部斑块受体ApsB（裂变酵母Mto 1）之间。隔膜MTOC由γ-TuRC组成，包括MztA，但通过AspB和Spa 18（裂殖酵母Mto 2）锚定。MztA是不是必不可少的活力，虽然异常纺锤体中经常观察到缺乏MztA的细胞。定量PALM成像揭示了SPBs的蛋白质组成的意想不到的动力学，随着时间的推移，在间期和有丝分裂期间的恒定数量的γ-微管蛋白复合物的数量的变化。
Centrosomes are important microtubule-organizing centers (MTOCs) in animal cells. In addition, non-centrosomal MTOCs (ncMTOCs) are found in many cell types. Their composition and structure are only poorly understood. Here, we analyzed nuclear MTOCs (spindle-pole bodies, SPBs) and septal MTOCs in Aspergillus nidulans. They both contain gamma-tubulin along with members of the family of gamma-tubulin complex proteins (GCPs). Our data suggest that SPBs consist of gamma-tubulin small complexes (gamma-TuSCs) at the outer plaque, and larger gamma-tubulin ring complexes (gamma-TuRC) at the inner plaque. We show that the MztA protein, an ortholog of the human MOZART protein (also known as MZT1), interacted with the inner plaque receptor PcpA (the homolog of fission yeast Pcp1) at SPBs, while no interaction nor colocalization was detected between MztA and the outer plaque receptor ApsB (fission yeast Mto1). Septal MTOCs consist of gamma-TuRCs including MztA but are anchored through AspB and Spa18 (fission yeast Mto2). MztA is not essential for viability, although abnormal spindles were observed frequently in cells lacking MztA. Quantitative PALM imaging revealed unexpected dynamics of the protein composition of SPBs, with changing numbers of gamma-tubulin complexes over time during interphase and constant numbers during mitosis.This article has an associated First Person interview with the first author of the paper.