Analysis of the local organization and dynamics of cellular actin networks

• Published in: The Journal of cell biology Vol. 202; no. 7; pp. 1057 - 1073
• Main Authors: Luo, Weiwei, Yu, Cheng-han, Lieu, Zi Zhao, Allard, Jun, Mogilner, Alex, Sheetz, Michael P, Bershadsky, Alexander D
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 30.09.2013; The Rockefeller University Press
• Subjects: Actin Cytoskeleton - physiology; Actomyosin - metabolism; Adaptor Proteins, Signal Transducing - metabolism; Animals; Blotting, Western; Cells; Cells, Cultured; Computer Simulation; Cytoplasm; Embryo, Mammalian - cytology; Embryo, Mammalian - metabolism; Fetal Proteins - metabolism; Fibroblasts - cytology; Fibroblasts - metabolism; Filamins - physiology; Fluorescent Antibody Technique; HeLa Cells; Humans; Image Processing, Computer-Assisted; Immunoenzyme Techniques; Membrane Proteins - metabolism; Mice; Mice, Knockout; Microfilament Proteins - antagonists & inhibitors; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; Models, Theoretical; Myosin Type II - metabolism; Nuclear Proteins - metabolism; Phosphoproteins - metabolism; Proteins; rho GTP-Binding Proteins - antagonists & inhibitors; rho GTP-Binding Proteins - genetics; rho GTP-Binding Proteins - metabolism; RNA, Small Interfering - genetics
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.201210123

Actin filaments, with the aid of multiple accessory proteins, self-assemble into a variety of network patterns. We studied the organization and dynamics of the actin network in nonadhesive regions of cells bridging fibronectin-coated adhesive strips. The network was formed by actin nodes associated with and linked by myosin II and containing the formin disheveled-associated activator of morphogenesis 1 (DAAM1) and the cross-linker filamin A (FlnA). After Latrunculin A (LatA) addition, actin nodes appeared to be more prominent and demonstrated drift-diffusion motion. Superresolution microscopy revealed that, in untreated cells, DAAM1 formed patches with a similar spatial arrangement to the actin nodes. Node movement (diffusion coefficient and velocity) in LatA-treated cells was dependent on the level and activity of myosin IIA, DAAM1, and FlnA. Based on our results, we developed a computational model of the dynamic formin-filamin-actin asters that can self-organize into a contractile actomyosin network. We suggest that such networks are critical for connecting distant parts of the cell to maintain the mechanical coherence of the cytoplasm.