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Self-organized wave-like beating of actin bundles in a minimal actomyosin system

Abstract : The emergent active behaviors of molecular motors assemblies and cytoskeletal filaments systems remain poorly understood, though individual molecules have been extensively characterized. By controlling the geometry of actin polymerization with surface micropatterns of a nucleation promoting factor, we were able to demonstrate in vitro the emergence of flagellar-like beating of bundles of parallel actin filaments in the presence of myosin motors. We worked with both myosin V and heavy-meromyosin II. The waveform of oscillation was similar for the two types of motors, but oscillations with myosin II were one order of magnitude faster than with myosin Va. In both cases, a bending wave traveled at a uniform speed from the anchored base of the actin bundle towards the tip. As polymerization occurred, the actin bundle elongated at a constant speed, resulting in an increase of the oscillation period, but the speed of the traveling bending wave remains constant. GFP-tagged myosin V revealed the presence of a myosin concentration peak within the actin bundle. Strikingly, myosin V motors were locally recruited within the actin bundle, before a concentration wave propagated towards the bundle’s tip in concert with the actin bending wave. These results revealed a novel form of coupling between the myosin affinity for actin and the actin bundle shape. Our work demonstrates that active flagellar-like beating emerges as an intrinsic property of polar bundles of filaments in interaction with molecular motors. Structural control over the self-assembly process provides key information to clarify the underlying physical principles of flagellar-like beating.
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  • HAL Id : tel-02409881, version 1

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Marie Pochitaloff-Huvalé. Self-organized wave-like beating of actin bundles in a minimal actomyosin system. Chemical Physics [physics.chem-ph]. Sorbonne Université, 2018. English. ⟨NNT : 2018SORUS318⟩. ⟨tel-02409881⟩

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