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J Cell Sci. 2018 Dec 11;132(4). pii: jcs219899. doi: 10.1242/jcs.219899.

Myosin-II activity generates a dynamic steady state with continuous actin turnover in a minimal actin cortex.

Author information

1
Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
2
Max Planck Institute of Biochemistry, 82152 Martinsried, Germany schwille@biochem.mpg.de.

Abstract

Dynamic reorganization of the actomyosin cytoskeleton allows fast modulation of the cell surface, which is vital for many cellular functions. Myosin-II motors generate the forces required for this remodeling by imparting contractility to actin networks. However, myosin-II activity might also have a more indirect contribution to cytoskeletal dynamics; it has been proposed that myosin activity increases actin turnover in various cellular contexts, presumably by enhancing disassembly. In vitro reconstitution of actomyosin networks has confirmed the role of myosin in actin network disassembly, but the reassembly of actin in these assays was limited by factors such as diffusional constraints and the use of stabilized actin filaments. Here, we present the reconstitution of a minimal dynamic actin cortex, where actin polymerization is catalyzed on the membrane in the presence of myosin-II activity. We demonstrate that myosin activity leads to disassembly and redistribution in this simplified cortex. Consequently, a new dynamic steady state emerges in which the actin network undergoes constant turnover. Our findings suggest a multifaceted role of myosin-II in the dynamics of the eukaryotic actin cortex. This article has an associated First Person interview with the first author of the paper.

KEYWORDS:

Cytoskeletal dynamics; In vitro reconstitution; Supported lipid bilayer; Synthetic biology; WASP

PMID:
30538127
DOI:
10.1242/jcs.219899
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Conflict of interest statement

Competing interestsThe authors declare no competing or financial interests.

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