Institute of Physiology and Pathophysiology, Department of Molecular Cell Physiology, Philipps-University Marburg, Marburg, Germany.
Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany.
Nat Commun. 2022 May 6;13(1):2492. doi: 10.1038/s41467-022-30167-0.
Changes in cell morphology require the dynamic remodeling of the actin cytoskeleton. Calcium fluxes have been suggested as an important signal to rapidly relay information to the actin cytoskeleton, but the underlying mechanisms remain poorly understood. Here, we identify the EF-hand domain containing protein EFhD2/Swip-1 as a conserved lamellipodial protein strongly upregulated in Drosophila macrophages at the onset of metamorphosis when macrophage behavior shifts from quiescent to migratory state. Loss- and gain-of-function analysis confirm a critical function of EFhD2/Swip-1 in lamellipodial cell migration in fly and mouse melanoma cells. Contrary to previous assumptions, TIRF-analyses unambiguously demonstrate that EFhD2/Swip-1 proteins efficiently cross-link actin filaments in a calcium-dependent manner. Using a single-cell wounding model, we show that EFhD2/Swip-1 promotes wound closure in a calcium-dependent manner. Mechanistically, our data suggest that transient calcium bursts reduce EFhD2/Swip-1 cross-linking activity and thereby promote rapid reorganization of existing actin networks to drive epithelial wound closure.
细胞形态的变化需要肌动蛋白细胞骨架的动态重塑。钙通量被认为是一种将信息快速传递到肌动蛋白细胞骨架的重要信号，但潜在的机制仍知之甚少。在这里，我们确定 EF 手结构域蛋白 EFhD2/Swip-1 作为一个保守的片状伪足蛋白，在果蝇巨噬细胞变态时强烈上调，此时巨噬细胞的行为从静止状态转变为迁移状态。EFhD2/Swip-1 的缺失和功能获得分析证实了 EFhD2/Swip-1 在果蝇和小鼠黑素瘤细胞片状伪足细胞迁移中的关键作用。与之前的假设相反，TIRF 分析明确表明 EFhD2/Swip-1 蛋白以钙依赖的方式有效地交联肌动蛋白丝。使用单细胞划痕模型，我们表明 EFhD2/Swip-1 以钙依赖的方式促进伤口闭合。从机制上讲，我们的数据表明，短暂的钙爆发降低了 EFhD2/Swip-1 的交联活性，从而促进了现有肌动蛋白网络的快速重组，以驱动上皮伤口闭合。
