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Abstract Understanding the behaviors of contractile actomyosin systems requires precise spatiotemporal control of filamentous myosin activity. Here, we develop a tool for optical control of contractility by extending the MyLOV family of gearshifting motors to create engineered filamentous myosins that change velocity in response to blue light. We characterize these minifilaments usingin vitrosingle-molecule tracking assays, contractility assays in reconstituted actin networks, and imaging of contractile phenotypes inDrosophilaS2 cells. The minifilaments change speed and/or direction when illuminated, display speeds that fall within and beyond the relevant physiological range, and display high processivities. Additionally, minifilament-driven contraction rates increase in blue light bothin vitroand in S2 cells. Finally, we develop an alternative design for minifilaments that only interact processively with actin in blue light. Engineered minifilaments can be used to dissect behaviors such as self-organization and mechanotransduction in contractile systems bothin vitroand in cells and tissues.
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FLN ‐1/filamin is required to anchor the actomyosin cytoskeleton and for global organization of sub‐cellular organelles in a contractile tissue
Abstract Actomyosin networks are organized in space, direction, size, and connectivity to produce coordinated contractions across cells. We use theC. elegansspermatheca, a tube composed of contractile myoepithelial cells, to study how actomyosin structures are organized. FLN‐1/filamin is required for the formation and stabilization of a regular array of parallel, contractile, actomyosin fibers in this tissue. Loss offln‐1results in the detachment of actin fibers from the basal surface, which then accumulate along the cell junctions and are stabilized by spectrin. In addition, actin and myosin are captured at the nucleus by the linker of nucleoskeleton and cytoskeleton complex (LINC) complex, where they form large foci. Nuclear positioning and morphology, distribution of the endoplasmic reticulum and the mitochondrial network are also disrupted. These results demonstrate that filamin is required to prevent large actin bundle formation and detachment, to prevent excess nuclear localization of actin and myosin, and to ensure correct positioning of organelles.
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- Award ID(s):
- 1816640
- PAR ID:
- 10455405
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Cytoskeleton
- Volume:
- 77
- Issue:
- 10
- ISSN:
- 1949-3584
- Format(s):
- Medium: X Size: p. 379-398
- Size(s):
- p. 379-398
- Sponsoring Org:
- National Science Foundation
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