Immobile myosin-II plays a scaffolding role during cytokinesis in budding yeast

Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104.
The Journal of Cell Biology (Impact Factor: 9.83). 01/2013; 200(3). DOI: 10.1083/jcb.201208030
Source: PubMed


Core components of cytokinesis are conserved from yeast to human, but how these components are assembled into a robust machine that drives cytokinesis remains poorly understood. In this paper, we show by fluorescence recovery after photobleaching analysis that Myo1, the sole myosin-II in budding yeast, was mobile at the division site before anaphase and became immobilized shortly before cytokinesis. This immobility was independent of actin filaments or the motor domain of Myo1 but required a small region in the Myo1 tail that is thought to be involved in higher-order assembly. As expected, proteins involved in actin ring assembly (tropomyosin and formin) and membrane trafficking (myosin-V and exocyst) were dynamic during cytokinesis. Strikingly, proteins involved in septum formation (the chitin synthase Chs2) and/or its coordination with the actomyosin ring (essential light chain, IQGAP, F-BAR, etc.) displayed Myo1-dependent immobility during cytokinesis, suggesting that Myo1 plays a scaffolding role in the assembly of a cytokinesis machine.

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Available from: Erfei Bi, May 13, 2014
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    • "The fact that CAR contraction fails in iqg1-1 is intriguing in the light of recent evidence demonstrating that the force generation required for contraction derives from actin disassembly and that Myo1 serves as a CAR scaffold but is not required for contractile force [53], [54]. Iqg1p was suggested to act as a cross-linker between actin filaments [55], a necessary function if contractile force is driven by filament disassembly, and the data presented here are consistent with that proposal. "
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