Abstract
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.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Actin Cytoskeleton / physiology*
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Actomyosin / metabolism
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Adaptor Proteins, Signal Transducing / metabolism
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Animals
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Blotting, Western
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Cells, Cultured
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Computer Simulation
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Embryo, Mammalian / cytology
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Embryo, Mammalian / metabolism*
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Fetal Proteins / metabolism
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Fibroblasts / cytology
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Fibroblasts / metabolism*
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Filamins / physiology*
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Fluorescent Antibody Technique
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Formins
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HeLa Cells
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Humans
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Image Processing, Computer-Assisted
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Immunoenzyme Techniques
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Membrane Proteins / metabolism
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Mice
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Mice, Knockout
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Microfilament Proteins / antagonists & inhibitors
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Microfilament Proteins / genetics
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Microfilament Proteins / metabolism*
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Models, Theoretical
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Myosin Type II / metabolism*
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Nuclear Proteins / metabolism
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Phosphoproteins / metabolism
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RNA, Small Interfering / genetics
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rho GTP-Binding Proteins / antagonists & inhibitors
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rho GTP-Binding Proteins / genetics
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rho GTP-Binding Proteins / metabolism*
Substances
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Adaptor Proteins, Signal Transducing
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Fetal Proteins
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Filamins
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FlnA protein, mouse
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Formins
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Lat protein, mouse
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Membrane Proteins
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Microfilament Proteins
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Nuclear Proteins
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Phosphoproteins
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RNA, Small Interfering
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Actomyosin
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Daam1 protein, mouse
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Myosin Type II
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rho GTP-Binding Proteins