Regulation of mitosis by the NIMA kinase involves TINA and its newly discovered partner, An-WDR8, at spindle pole bodies.
Regulation of mitosis by the NIMA kinase involves TINA and its newly discovered partner, An-WDR8, at spindle pole bodies.
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DOI：
10.1091/mbc.e13-07-0422
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发表时间：
2013-12
影响因子：
3.3
通讯作者：
Osmani SA
中科院分区：
文献类型：
--
作者：
Shen KF;Osmani SA
有丝分裂需要在纺锤体极体上触发事件，包括纺锤体微管的播种和锚定。对 NIMA 激酶和有丝分裂 SPB 蛋白 TINA 的分析扩展了我们对靶向 SPB 的有丝分裂特异性蛋白的理解，并表明锚定在 SPB 上的微管涉及 TINA 及其新鉴定的伙伴 An-WDR8。 NIMA 激酶是有丝分裂核孔复合体分解所必需的，并且可能控制其他有丝分裂特异性事件。为了研究这种可能性，我们使用四维转盘共聚焦显微镜对 NIMA-绿色荧光蛋白 (GFP) 进行成像。在有丝分裂时，NIMA-GFP 定位于纺锤体极体 (SPB)，其中包含 Cdk1/细胞周期蛋白 B，然后是 Aurora、TINA 和 BimC 驱动蛋白。 NIMA 从 SPB 附近开始以空间调节的方式促进 NPC 分解。 NIMA 也是 TINA（一种 NIMA 相互作用蛋白）在有丝分裂起始期间定位到 SPB 所必需的，而 TINA 也是在有丝分裂进展期间将 NIMA 定位回 SPB 所必需的。为了帮助扩展 NIMA-TINA 途径，我们亲和纯化了 TINA，并发现它能够与 An-WDR8（一种从人类到植物中保守的 WD40 结构域蛋白）独特地共纯化。与 TINA 一样，An-WDR8 在 G2 期间在细胞核内积累，但在定位到有丝分裂 SPB 之前从细胞核中分散。如果没有 An-WDR8，TINA 水平会大大降低，而 TINA 对于 An-WDR8 有丝分裂靶向是必需的。最后，我们证明 TINA 是将有丝分裂微管锚定到 SPB 上，并与 An-WDR8 结合，以实现成功的有丝分裂。这些发现为 SPB 靶向提供了新的见解，并表明 SPB 处的有丝分裂微管锚定系统涉及与 TINA 复合的 WDR8。
Mitosis requires events triggered at spindle pole bodies, including seeding and anchoring of spindle microtubules. Analysis of the NIMA kinase and the mitotic SPB protein TINA extends our understanding of mitotic-specific protein targeting to SPBs and indicates that microtubule anchoring at SPBs involves TINA and its newly identified partner, An-WDR8. The NIMA kinase is required for mitotic nuclear pore complex disassembly and potentially controls other mitotic-specific events. To investigate this possibility, we imaged NIMA–green fluorescent protein (GFP) using four-dimensional spinning disk confocal microscopy. At mitosis NIMA-GFP locates to spindle pole bodies (SPBs), which contain Cdk1/cyclin B, followed by Aurora, TINA, and the BimC kinesin. NIMA promotes NPC disassembly in a spatially regulated manner starting near SPBs. NIMA is also required for TINA, a NIMA-interacting protein, to locate to SPBs during initiation of mitosis, and TINA is then necessary for locating NIMA back to SPBs during mitotic progression. To help expand the NIMA-TINA pathway, we affinity purified TINA and found it to uniquely copurify with An-WDR8, a WD40-domain protein conserved from humans to plants. Like TINA, An-WDR8 accumulates within nuclei during G2 but disperses from nuclei before locating to mitotic SPBs. Without An-WDR8, TINA levels are greatly reduced, whereas TINA is necessary for mitotic targeting of An-WDR8. Finally, we show that TINA is required to anchor mitotic microtubules to SPBs and, in combination with An-WDR8, for successful mitosis. The findings provide new insights into SPB targeting and indicate that the mitotic microtubule-anchoring system at SPBs involves WDR8 in complex with TINA.