Mitotic exit kinase Dbf2 directly phosphorylates chitin synthase Chs2 to regulate cytokinesis in budding yeast.
Mitotic exit kinase Dbf2 directly phosphorylates chitin synthase Chs2 to regulate cytokinesis in budding yeast.
复制标题
有丝分裂退出激酶 Dbf2 直接磷酸化几丁质合酶 Chs2，以调节芽殖酵母中的胞质分裂。
DOI：
10.1091/mbc.e12-01-0033
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发表时间：
2012
影响因子：
3.3
通讯作者：
Bi,Erfei
中科院分区：
文献类型：
--
作者：
Oh,Younghoon;Chang,Kuang-Jung;Orlean,Peter;Wloka,Carsten;Deshaies,Raymond;Bi,Erfei
胞质分裂过程中细胞周期机制如何调节细胞外基质（ECM）重塑仍知之甚少。在芽殖酵母酿酒酵母中，初级隔膜（PS）是动物ECM的功能等同物，在胞质分裂期间由几丁质合酶Chs 2合成。在这里，我们报告Dbf 2，一个保守的有丝分裂出口激酶，定位于分裂位点后Chs 2和直接磷酸化Chs 2的几个残基，包括Ser-217。磷酸缺陷型（chs 2-S217 A）和拟磷酸型（chs 2-S217 D）突变均导致胞质分裂缺陷，表明Ser-217的动态磷酸化-去磷酸化对Chs 2功能至关重要。令人惊讶的是，Chs 2-S217 A与肌动球蛋白环（AMR）不对称地收缩，而Chs 2-S217 D几乎没有收缩，并且在分裂位点保持高度移动的。这些数据表明，Dbf 2的Chs 2磷酸化触发其在胞质分裂的后期阶段从AMR解离。有趣的是，增加剂量的Cyk 3强烈抑制了chs 2-S217 A和chs 2-S217 D突变体，Cyk 3是一种胞质分裂蛋白，显示Dbf 2依赖性定位，也刺激Chs 2介导的几丁质合成。因此Dbf 2至少通过两条独立的途径调节PS的形成：直接磷酸化和Cyk 3介导的Chs 2激活。我们的研究建立了一个机制，直接细胞周期控制细胞质分裂过程中的ECM重塑。
How cell cycle machinery regulates extracellular matrix (ECM) remodeling during cytokinesis remains poorly understood. In the budding yeastSaccharomyces cerevisiae, the primary septum (PS), a functional equivalent of animal ECM, is synthesized during cytokinesis by the chitin synthase Chs2. Here, we report that Dbf2, a conserved mitotic exit kinase, localizes to the division site after Chs2 and directly phosphorylates Chs2 on several residues, including Ser-217. Both phosphodeficient (chs2‑S217A) and phosphomimic (chs2‑S217D) mutations cause defects in cytokinesis, suggesting that dynamic phosphorylation–dephosphorylation of Ser-217 is critical for Chs2 function. It is striking that Chs2‑S217A constricts asymmetrically with the actomyosin ring (AMR), whereas Chs2-S217D displays little or no constriction and remains highly mobile at the division site. These data suggest that Chs2 phosphorylation by Dbf2 triggers its dissociation from the AMR during the late stage of cytokinesis. Of interest, bothchs2‑S217Aandchs2‑S217Dmutants are robustly suppressed by increased dosage of Cyk3, a cytokinesis protein that displays Dbf2‑dependent localization and also stimulates Chs2‑mediated chitin synthesis. Thus Dbf2 regulates PS formation through at least two independent pathways: direct phosphorylation and Cyk3‑mediated activation of Chs2. Our study establishes a mechanism for direct cell cycle control of ECM remodeling during cytokinesis.