Okada Hiroki, Wloka Carsten, Wu Jian-Qiu, Bi Erfei
Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AE Groningen, The Netherlands.
iScience. 2019 Apr 26;14:69-87. doi: 10.1016/j.isci.2019.03.014. Epub 2019 Mar 16.
To address the question of why more than one myosin-II isoform is expressed in a single cell to drive cytokinesis, we analyzed the roles of the myosin-II isoforms, Myo2 and Myp2, of the fission yeast Schizosaccharomyces pombe, in cytokinesis under normal and stressed conditions. We found that Myp2 controls the disassembly, stability, and constriction initiation of the Myo2 ring in response to high-salt stress. A C-terminal coiled-coil domain of Myp2 is required for its immobility and contractility during cytokinesis, and when fused to the tail of the dynamic Myo2, renders the chimera the low-turnover property. We also found, by following distinct processes in real time at the single-cell level, that Myo2 and Myp2 are differentially required but collectively essential for guiding extracellular matrix remodeling during cytokinesis. These results suggest that the dynamic and immobile myosin-II isoforms are evolved to carry out cytokinesis with robustness under different growth conditions.
为了解决为什么单个细胞中会表达不止一种肌球蛋白-II 异构体来驱动胞质分裂这一问题，我们分析了裂殖酵母粟酒裂殖酵母中肌球蛋白-II 异构体 Myo2 和 Myp2 在正常和应激条件下胞质分裂中的作用。我们发现，Myp2 在高盐应激下控制 Myo2 环的解体、稳定性和收缩起始。Myp2 的 C 末端卷曲螺旋结构域是其在胞质分裂过程中保持固定和收缩能力所必需的，当与动态的 Myo2 的尾部融合时，会使嵌合体具有低周转率特性。我们还通过在单细胞水平实时跟踪不同过程发现，Myo2 和 Myp2 在胞质分裂过程中对引导细胞外基质重塑的需求不同，但共同发挥作用至关重要。这些结果表明，动态和固定的肌球蛋白-II 异构体是为了在不同生长条件下稳健地进行胞质分裂而进化出来的。
