Department of Cell Biology (Anatomy III), Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
Department of Cardiovascular Physiology and Pathophysiology, Walter Brendel Centre of Experimental Medicine, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
Eur J Cell Biol. 2017 Sep;96(6):553-566. doi: 10.1016/j.ejcb.2017.05.004. Epub 2017 May 27.
The primary defense machinery to combat inflammation involves neutrophil granulocytes which in order to execute their functions rely on the efficiency of different cellular mechanisms including adhesion, spreading, migration in different environments, and phagocytosis. These functions require an accurately regulated actin network as well as the activation and adjustment of various signaling pathways. Mammalian filamins (FLNs) comprise three highly homologous large actin-binding proteins that are obvious candidates to control these processes as FLNs have been described to play a role in migration, spreading and adhesion in a variety of different cell types. The present study analyzed the role of filamin A (FLNa) in human neutrophil-like HL-60 cells. We found a strong enrichment of FLNa at the uropod of migrating neutrophils, and show that deficiency of FLNa caused a decrease in speed of migration both in 2D and 3D that is accompanied by a reduced activation of myosin-II. In addition, we show that FLNa plays a role in neutrophil phagocytosis. We also identified a hitherto unknown interaction of FLNa with coronin 1A that is mediated by FLNa repeats 9-18. FLNa deficiency had no or only minor effects on cell adhesion and spreading. In summary, deficiency of FLNa in human neutrophil-like HL-60 cells resulted in a surprisingly subtle phenotype. Our data indicate that FLNa is not essential for the regulation of mechanical properties during migration, but contributes to motility in a modulatory manner probably through its action at the uropod.
对抗炎症的主要防御机制涉及中性粒细胞粒细胞，为了执行其功能，它们依赖于不同的细胞机制的效率，包括在不同环境中的粘附、扩散、迁移和吞噬作用。这些功能需要一个精确调节的肌动蛋白网络，以及各种信号通路的激活和调整。哺乳动物细丝蛋白（FLNs）包括三种高度同源的大型肌动蛋白结合蛋白，它们显然是控制这些过程的候选者，因为已经描述过 FLNs 在各种不同的细胞类型中在迁移、扩散和粘附中发挥作用。本研究分析了丝状蛋白 A (FLNa) 在人中性粒细胞样 HL-60 细胞中的作用。我们发现 FLNa 在迁移中性粒细胞的尾端强烈富集，并表明 FLNa 的缺乏导致 2D 和 3D 中迁移速度的降低，这伴随着肌球蛋白-II 的激活减少。此外，我们表明 FLNa 在中性粒细胞吞噬作用中发挥作用。我们还发现了 FLNa 与冠状蛋白 1A 之间以前未知的相互作用，该相互作用由 FLNa 重复 9-18 介导。FLNa 缺乏对细胞粘附和扩散几乎没有或只有轻微的影响。总之，人中性粒细胞样 HL-60 细胞中 FLNa 的缺乏导致了惊人的微妙表型。我们的数据表明，FLNa 对于迁移过程中机械性能的调节不是必需的，但可能通过其在尾端的作用以调节方式促进运动。
