Centrosomes are important microtubule-organizing centers (MTOC) in animal cells. In addition, non-centrosomal MTOCs (ncMTOCs) have been described in many cell types. The functional analogs of centrosomes in fungi are the spindle pole bodies (SPBs). In Aspergillus nidulans, additional MTOCs have been discovered at septa (sMTOC). Although the core components are conserved in both MTOCs, their composition and organization are different and dynamic. Here, we show that the polo-like kinase PlkA binds the γ-tubulin ring complex (γ-TuRC) receptor protein ApsB and contributes to targeting ApsB to both MTOCs. PlkA coordinates the activities of the SPB outer plaque and the sMTOC. PlkA kinase activity was required for astral MT formation involving ApsB recruitment. PlkA also interacted with the γ-TuRC inner plaque receptor protein PcpA. Mitosis was delayed without PlkA, and the PlkA protein was required for proper mitotic spindle morphology, although this function was independent of its catalytic activity. Our results suggest that the polo-like kinase is a regulator of MTOC activities and acts as a scaffolding unit through interaction with γ-TuRC receptors.

中文翻译：

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构巢曲霉 polo 样激酶 PlkA 在微管组织中心控制中的作用。

中心体是动物细胞中重要的微管组织中心 (MTOC)。此外，已经在许多细胞类型中描述了非中心体 MTOCs (ncMTOCs)。真菌中中心体的功能类似物是纺锤体极体 (SPB)。在构巢曲霉中，在隔垫 (sMTOC) 中发现了额外的 MTOC。尽管核心组件在两个 MTOC 中都是保守的，但它们的组成和组织是不同的和动态的。在这里，我们展示了 polo 样激酶 PlkA 结合 γ-微管蛋白环复合物 (γ-TuRC) 受体蛋白 ApsB，并有助于将 ApsB 靶向两个 MTOC。PlkA 协调 SPB 外斑块和 sMTOC 的活动。涉及 ApsB 募集的星体 MT 形成需要 PlkA 激酶活性。PlkA 还与 γ-TuRC 内斑块受体蛋白 PcpA 相互作用。有丝分裂在没有 PlkA 的情况下被延迟，并且 PlkA 蛋白是适当的有丝分裂纺锤体形态所必需的，尽管这种功能与其催化活性无关。我们的结果表明 polo 样激酶是 MTOC 活性的调节剂，并通过与 γ-TuRC 受体的相互作用充当支架单位。