Generation of contractile actomyosin bundles depends on mechanosensitive actin filament assembly and disassembly

eLife

Ramaswamy Krishnan¹  Amjad Husain¹  Gergana Gateva²  Pekka Lappalainen²  Sari Tojkander² 

[1] Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States;Institute of Biotechnology, University of Helsinki, Helsinki, Finland;

关键词: actin;    stress fibers;    mechanosensing;   

DOI  :  10.7554/eLife.06126

来源: DOAJ

【 摘 要 】

Adhesion and morphogenesis of many non-muscle cells are guided by contractile actomyosin bundles called ventral stress fibers. While it is well established that stress fibers are mechanosensitive structures, physical mechanisms by which they assemble, align, and mature have remained elusive. Here we show that arcs, which serve as precursors for ventral stress fibers, undergo lateral fusion during their centripetal flow to form thick actomyosin bundles that apply tension to focal adhesions at their ends. Importantly, this myosin II-derived force inhibits vectorial actin polymerization at focal adhesions through AMPK-mediated phosphorylation of VASP, and thereby halts stress fiber elongation and ensures their proper contractility. Stress fiber maturation additionally requires ADF/cofilin-mediated disassembly of non-contractile stress fibers, whereas contractile fibers are protected from severing. Taken together, these data reveal that myosin-derived tension precisely controls both actin filament assembly and disassembly to ensure generation and proper alignment of contractile stress fibers in migrating cells.

【 授权许可】

Unknown