Wang Xinyan, Huang Shuai, Zheng Cunni, Ge Wei, Wu Chuanyue, Tse Yu Chung
Department of Biology.
Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, China, and.
G3 (Bethesda). 2020 Jul 7;10(7):2507-2517. doi: 10.1534/g3.120.401185.
Egg-laying behavior in is a well-known model for investigating fundamental cellular processes. In egg-laying, muscle contraction is the relaxation of the vulval muscle to extrude eggs from the vulva. Unlike skeletal muscle, vulval muscle lacks visible striations of the sarcomere. Therefore, vulval muscle must counteract the mechanical stress, caused by egg extrusion and body movement, from inducing cell-shape distortion by maintaining its cytoskeletal integrity. However, the underlying mechanisms that regulate the cellular integrity in vulval muscles remain unclear. Here, we demonstrate that egg-laying requires proper vulval muscle 1 (vm1), in which the actin bundle organization of vm1 muscles is regulated by Ras suppressor protein 1 (RSU-1). In the loss of RSU-1, as well as Ras overactivation, blister-like membrane protrusions and disorganized actin bundles were observed in the vm1 muscles. Moreover, Ras depletion diminished the defected actin-bundles in mutant. These results reveal the genetic interaction of RSU-1 and Ras In addition, our results further demonstrated that the fifth to seventh leucine-rich region of RSU-1 is required to promote actin-bundling protein, α-actinin, for actin bundle stabilization in the vm1 muscles. This expands our understanding of the molecular mechanisms of actin bundle organization in a specialized smooth muscle.
产卵行为是研究基本细胞过程的一个著名模型。在产卵过程中，肌肉收缩是外阴肌肉的松弛，以便将卵从外阴挤出。与骨骼肌不同，外阴肌肉缺乏肌节可见的条纹。因此，外阴肌肉必须通过维持其细胞骨架完整性来抵消由卵挤出和身体运动引起的机械应力，防止细胞形状变形。然而，调节外阴肌肉细胞完整性的潜在机制仍不清楚。在这里，我们证明产卵需要适当的外阴肌肉1（vm1），其中vm1肌肉的肌动蛋白束组织由Ras抑制蛋白1（RSU-1）调节。在RSU-1缺失以及Ras过度激活的情况下，在vm1肌肉中观察到水泡样膜突起和紊乱的肌动蛋白束。此外，Ras缺失减少了突变体中缺陷的肌动蛋白束。这些结果揭示了RSU-1和Ras的遗传相互作用。此外，我们的结果进一步证明，RSU-1的第五至第七富含亮氨酸区域是促进肌动蛋白束稳定蛋白α-辅肌动蛋白在vm1肌肉中稳定肌动蛋白束所必需的。这扩展了我们对特殊平滑肌中肌动蛋白束组织分子机制的理解。
