Self-organization of waves and pulse trains by molecular motors in cellular protrusions.
Actin-based cellular protrusions are an ubiquitous feature of cells, performing a variety of critical functions ranging from cell-cell communication to cell motility. The formation and maintenance of these protrusions relies on the transport of proteins via myosin motors, to the protrusion tip. While tip-directed motion leads to accumulation of motors (and their molecular cargo) at the protrusion tip, it is observed that motors also form rearward moving, periodic and isolated aggregates. The origins and mechanisms of these aggregates, and whether they are important for the recycling of motors, remain open puzzles. Motivated by novel myosin-XV experiments, a mass conserving reaction-diffusion-advection model is proposed. The model incorporates a non-linear cooperative interaction between motors, which converts them between an active and an inactive state. Specifically, the type of aggregate formed (traveling waves or pulse-trains) is linked to the kinetics of motors at the protrusion tip which is introduced by a boundary condition. These pattern selection mechanisms are found not only to qualitatively agree with empirical observations but open new vistas to the transport phenomena by molecular motors in general.
Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion 84990, Israel.
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Yochelis
Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, 50 South Drive, Bethesda, MD 20892-8027, USA.
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Ebrahim
Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, 50 South Drive, Bethesda, MD 20892-8027, USA.
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Millis
Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, 50 South Drive, Bethesda, MD 20892-8027, USA.
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Cui
Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, 50 South Drive, Bethesda, MD 20892-8027, USA.
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Kachar
Department of Chemical Physics, Weizmann Institute of Science, P.O.B. 26, Rehovot, Israel 76100.
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Naoz
Department of Chemical Physics, Weizmann Institute of Science, P.O.B. 26, Rehovot, Israel 76100.
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D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D048429:Cell Size; D022081:Cell Surface Extensions / Q000502:physiology*; D003198:Computer Simulation; D006801:Humans; D008560:Membrane Fluidity / Q000502:physiology*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000502:physiology*
D020409:Molecular Motor Proteins