Analysis of the local organization and dynamics of cellular actin networks |
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Authors: | Weiwei Luo Cheng-han Yu Zi Zhao Lieu Jun Allard Alex Mogilner Michael P. Sheetz Alexander D. Bershadsky |
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Affiliation: | 1.Mechanobiology Institute, National University of Singapore, Singapore 117411, Republic of Singapore;2.Department of Neurobiology, Physiology, and Behavior, and 3.Department of Mathematics, University of California at Davis, Davis, CA 95616;4.Department of Biological Sciences, Columbia University, New York, NY 10027;5.Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel |
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Abstract: | A ctin 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. |
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