1D.W., Johns Hopkins University, 3400 North Charles St., Croft Hall, Baltimore, MD 21218, USA.
FASEB J. 2013 Oct;27(10):4089-99. doi: 10.1096/fj.12-224352. Epub 2013 Jun 24.
Arp2/3 is a protein complex that nucleates actin filament assembly in the lamellipodium in adherent cells crawling on planar 2-dimensional (2D) substrates. However, in physiopathological situations, cell migration typically occurs within a 3-dimensional (3D) environment, and little is known about the role of Arp2/3 and associated proteins in 3D cell migration. Using time resolved live-cell imaging and HT1080, a fibrosarcoma cell line commonly used to study cell migration, we find that the Arp2/3 complex and associated proteins N-WASP, WAVE1, cortactin, and Cdc42 regulate 3D cell migration. We report that this regulation is caused by formation of multigeneration dendritic protrusions, which mediate traction forces on the surrounding matrix and effective cell migration. The primary protrusions emanating directly from the cell body and prolonging the nucleus forms independent of Arp2/3 and dependent on focal adhesion proteins FAK, talin, and p130Cas. The Arp2/3 complex, N-WASP, WAVE1, cortactin, and Cdc42 regulate the secondary protrusions branching off from the primary protrusions. In 3D matrices, fibrosarcoma cells as well as migrating breast, pancreatic, and prostate cancer cells do not display lamellipodial structures. This study characterizes the unique topology of protrusions made by cells in a 3D matrix and show that these dendritic protrusions play a critical role in 3D cell motility and matrix deformation. The relative contribution of these proteins to 3D migration is significantly different from their role in 2D migration.
Arp2/3 是一种蛋白质复合物，它在贴壁细胞的片状伪足中引发肌动蛋白丝的组装，这些细胞在平面二维（2D）基质上爬行。然而，在生理病理情况下，细胞迁移通常发生在三维（3D）环境中，关于 Arp2/3 及其相关蛋白在 3D 细胞迁移中的作用知之甚少。使用时间分辨活细胞成像和 HT1080（一种常用于研究细胞迁移的纤维肉瘤细胞系），我们发现 Arp2/3 复合物和相关蛋白 N-WASP、WAVE1、cortactin 和 Cdc42 调节 3D 细胞迁移。我们报告说，这种调节是由于多代树突状突起的形成引起的，这些突起在周围基质上产生牵引力，并促进有效的细胞迁移。直接从细胞体发出并延长细胞核的主要突起的形成不依赖于 Arp2/3，而是依赖于粘着斑蛋白 FAK、talin 和 p130Cas。Arp2/3 复合物、N-WASP、WAVE1、cortactin 和 Cdc42 调节从主突起分支出来的次级突起。在 3D 基质中，纤维肉瘤细胞以及迁移的乳腺癌、胰腺癌和前列腺癌细胞不显示片状伪足结构。本研究描述了细胞在 3D 基质中突起的独特拓扑结构，并表明这些树突状突起在 3D 细胞运动和基质变形中起着关键作用。这些蛋白在 3D 迁移中的相对贡献与它们在 2D 迁移中的作用显著不同。
