Control of Nonmuscle Myosins by Phosphorylation
- SourceAvailable from: Avril V Somlyo
The Journal of Physiology 01/2015; 593(2). DOI:10.1113/jphysiol.2014.285866 · 4.54 Impact Factor
- "On the other hand, polymerization and depolymerization of myosin filaments readily occurs and is necessary in cultured cells, cells undergoing mitosis, proliferation and migration such as during development, angiogenesis and tissue remodelling. Phosphorylation of RLC20 promotes filament assembly as originally shown in thymus cells (Scholey et al. 1980) and since reported in many non-muscle cells (Tan et al. 1992 "
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- "The canonical cytoplasmic myosin 1 isoform is known to undergo posttranslational modifications both within the neck domain and the C-terminal tail. Phosphorylation, arguably the best characterized modification (Tan et al., 1992 "
ABSTRACT: In the eukaryotic cell nucleus, actin and myosin are emerging as essential regulators of nuclear function. At gene level, they regulate chromatin and modulate RNA polymerase transcription, and at the RNA level, they are involved in the metabolism of ribonucleoprotein complexes. Furthermore, actin and myosin are involved in maintaining the structure of cell nucleus by mediating chromatin movement and by interacting with components of the nuclear lamina. This plethora of functions is now supported by evidence that nuclear actin polymerizes just like the cytoplasmic actin fraction. Based on these considerations, we now hypothesize that the nuclear myosin forms function as actin-based motors. In this chapter, our goal is to start from the knowledge acquired in the cytoplasmic field to explore how nuclear myosin functions in gene transcription. One of the pressing issues discussed here is whether nuclear myosin produces local tension or functions as transporters. Based on two current models reported in the literature, we discuss the topology of the actin-based nuclear myosin 1 motor and how it is believed to facilitate propulsion of the RNA polymerase machinery while maintaining chromatin that is compatible with transcription. These mechanisms will be placed in the context of cell cycle progression.International review of cell and molecular biology 01/2014; 311C:183-230. DOI:10.1016/B978-0-12-800179-0.00004-0 · 4.52 Impact Factor
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- "All myosin-IIs from animal cells can assemble into bipolar filaments in vitro, and this assembly invariably depends on a region near their C termini, called the assembly domain, which is required for antiparallel interaction of myosin-II molecules (Trybus, 1991; Tan et al., 1992). Myo1 tail also contains a putative assembly domain near its C terminus, which can only localize to Video 3, left); in contrast, Mlc1 (see Fig. 7 A and Video 8) and Iqg1 (see Fig. 7 B) displayed immobility throughout their localization at the division site. "
ABSTRACT: 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.The Journal of Cell Biology 01/2013; 200(3). DOI:10.1083/jcb.201208030 · 9.69 Impact Factor