The F-BAR protein Imp2 is an important contributor to cytokinesis in the fission yeast Schizosaccharomyces pombe. Because cell cycle-regulated phosphorylation of the central intrinsically disordered region (IDR) of the Imp2 paralog Cdc15 controls Cdc15 oligomerization state, localization and ability to bind protein partners, we investigated whether Imp2 is similarly phosphoregulated. We found that Imp2 is endogenously phosphorylated on 28 sites within its IDR, with the bulk of phosphorylation being constitutive. In vitro, the casein kinase 1 (CK1) isoforms Hhp1 and Hhp2 can phosphorylate 17 sites, and Cdk1 (also known as Cdc2) can phosphorylate the remaining 11 sites. Mutations that prevent Cdk1 phosphorylation result in precocious Imp2 recruitment to the cell division site, and mutations designed to mimic these phosphorylation events delay Imp2 accumulation at the contractile ring (CR). Mutations that eliminate CK1 phosphorylation sites allow CR sliding, and phosphomimetic substitutions at these sites reduce Imp2 protein levels and slow CR constriction. Thus, like Cdc15, the Imp2 IDR is phosphorylated at many sites by multiple kinases. In contrast to Cdc15, for which phosphorylation plays a major cell cycle regulatory role, Imp2 phosphorylation is primarily constitutive, with milder effects on localization and function. This article has an associated First Person interview with the first author of the paper.

中文翻译：

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F-BAR 蛋白 Imp2 内在无序区域的磷酸化调节其收缩环募集。

F-BAR 蛋白 Imp2 是裂殖酵母粟酒裂殖酵母胞质分裂的重要贡献者。因为 Imp2 paralog Cdc15 的中央固有无序区域 (IDR) 的细胞周期调节磷酸化控制 Cdc15 寡聚化状态、定位和结合蛋白质伴侣的能力，我们研究了 Imp2 是否同样受到磷酸调节。我们发现 Imp2 在其 IDR 内的 28 个位点内源性磷酸化，大部分磷酸化是组成型的。在体外，酪蛋白激酶 1 (CK1) 异构体 Hhp1 和 Hhp2 可以磷酸化 17 个位点，而 Cdk1（也称为 Cdc2）可以磷酸化剩余的 11 个位点。阻止 Cdk1 磷酸化的突变导致 Imp2 早熟募集到细胞分裂位点，旨在模拟这些磷酸化事件的突变会延迟 Imp2 在收缩环 (CR) 处的积累。消除 CK1 磷酸化位点的突变允许 CR 滑动，并且这些位点的拟磷取代降低了 Imp2 蛋白水平并减缓了 CR 收缩。因此，与 Cdc15 一样，Imp2 IDR 在许多位点被多种激酶磷酸化。与磷酸化在细胞周期调节中起主要作用的 Cdc15 相比，Imp2 磷酸化主要是组成型的，对定位和功能的影响较小。本文与论文的第一作者进行了相关的第一人称采访。因此，与 Cdc15 一样，Imp2 IDR 在许多位点被多种激酶磷酸化。与磷酸化在细胞周期调节中起主要作用的 Cdc15 相比，Imp2 磷酸化主要是组成型的，对定位和功能的影响较小。本文与论文的第一作者进行了相关的第一人称采访。因此，与 Cdc15 一样，Imp2 IDR 在许多位点被多种激酶磷酸化。与磷酸化在细胞周期调节中起主要作用的 Cdc15 相比，Imp2 磷酸化主要是组成型的，对定位和功能的影响较小。本文与论文的第一作者进行了相关的第一人称采访。