Plk1 negatively regulates PRC1 to prevent premature midzone formation before cytokinesis.
Plk1 negatively regulates PRC1 to prevent premature midzone formation before cytokinesis.
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DOI：
10.1091/mbc.e12-01-0058
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发表时间：
2012-07
影响因子：
3.3
通讯作者：
Mitchison TJ
中科院分区：
文献类型：
--
作者：
Hu CK;Ozlü N;Coughlin M;Steen JJ;Mitchison TJ
Plk1（而非 Cdk1）使 Thr-602 上的 PRC1 磷酸化，以防止中期中区过早组装。微管增强这种磷酸化。 Plk1、PRC1 和微管共同调节整个细胞分裂过程中的稳态 MT 捆绑。为了实现有丝分裂和胞质分裂，微管必须在细胞分裂的不同阶段组装成不同的结构——有丝分裂纺锤体在后期之前分离染色体，而中间区则使姐妹基因组分开并在后期之后引导分裂沟。这种时间调节被认为涉及 Cdk1 激酶，它在后期后以类似开关的方式失活。我们发现抑制 Plk1 会导致仍处于中期的细胞中的中区过早组装，从而破坏微管的时间调节。反平行微管成束蛋白 PRC1 在组织中区复合体中发挥着关键作用。我们发现 Plk1 通过 PRC1 C 末端附近的单个位点 Thr-602 的磷酸化来负向调节 PRC1。我们还发现微管通过 Plk1 刺激 Thr-602 磷酸化。这产生了控制 PRC1 活性的潜在负反馈回路。它还使得有丝分裂停滞期间 Thr-602 磷酸化的程度依赖于停滞药物的机制。出乎意料的是，我们无法检测到 PRC1 上 Cdk1 位点的后期前调控作用。我们认为 PRC1 受 Plk1 调节，而不是之前提出的 Cdk1 调节，因为它的活性必须在后期前和后期受到时空调节，而 Cdk1 活性对于此目的来说太二元化了。
Plk1, but not Cdk1, phosphorylates PRC1 on Thr-602 to prevent premature midzone assembly in metaphase. Microtubules enhance this phosphorylation. Plk1, PRC1, and microtubules together regulate homeostatic MT bundling throughout cell division. To achieve mitosis and cytokinesis, microtubules must assemble into distinct structures at different stages of cell division—mitotic spindles to segregate the chromosomes before anaphase and midzones to keep sister genomes apart and guide the cleavage furrow after anaphase. This temporal regulation is believed to involve Cdk1 kinase, which is inactivated in a switch-like way after anaphase. We found that inhibiting Plk1 caused premature assembly of midzones in cells still in metaphase, breaking the temporal regulation of microtubules. The antiparallel microtubule-bundling protein PRC1 plays a key role in organizing the midzone complex. We found that Plk1 negatively regulates PRC1 through phosphorylation of a single site, Thr-602, near the C-terminus of PRC1. We also found that microtubules stimulated Thr-602 phosphorylation by Plk1. This creates a potential negative feedback loop controlling PRC1 activity. It also made the extent of Thr-602 phosphorylation during mitotic arrest dependent on the mechanism of the arresting drug. Unexpectedly, we could not detect a preanaphase regulatory role for Cdk1 sites on PRC1. We suggest that PRC1 is regulated by Plk1, rather than Cdk1 as previously proposed, because its activity must be spatiotemporally regulated both preanaphase and postanaphase, and Cdk1 activity is too binary for this purpose.