Department of Biology, Drexel University, Philadelphia, PA 19104.
National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892.
Mol Biol Cell. 2019 May 1;30(10):1170-1181. doi: 10.1091/mbc.E18-06-0355. Epub 2019 Mar 13.
Two-dimensional (2D) substrate rigidity promotes myosin II activity to increase traction force in a process negatively regulated by tropomyosin (Tpm) 2.1. We recently discovered that actomyosin contractility can increase intracellular pressure and switch tumor cells from low-pressure lamellipodia to high-pressure lobopodial protrusions during three-dimensional (3D) migration. However, it remains unclear whether these myosin II-generated cellular forces are produced simultaneously, and by the same molecular machinery. Here we identify Tpm 1.6 as a positive regulator of intracellular pressure and confirm that Tpm 2.1 is a negative regulator of traction force. We find that Tpm 1.6 and 2.1 can control intracellular pressure and traction independently, suggesting these myosin II-dependent forces are generated by distinct mechanisms. Further, these tropomyosin-regulated mechanisms can be integrated to control complex cell behaviors on 2D and in 3D environments.
二维(2D)基质刚性通过肌球蛋白 II 活性促进牵引力的增加,这一过程受原肌球蛋白(Tpm)2.1 负调控。我们最近发现,在三维(3D)迁移过程中,肌动球蛋白的收缩性可以增加细胞内压力,并将肿瘤细胞从低压片状伪足切换为高压叶状伪足突起。然而,目前尚不清楚这些由肌球蛋白 II 产生的细胞力是否同时产生,并且是否由相同的分子机制产生。在这里,我们鉴定出 Tpm 1.6 是细胞内压力的正调节剂,并证实 Tpm 2.1 是牵引力的负调节剂。我们发现 Tpm 1.6 和 2.1 可以独立地控制细胞内压力和牵引力,这表明这些依赖肌球蛋白 II 的力是由不同的机制产生的。此外,这些原肌球蛋白调节的机制可以被整合来控制二维和三维环境中的复杂细胞行为。