Control of Nonmuscle Myosins by Phosphorylation

Department of Developmental Biology , Stanford University, Palo Alto, California, United States
Annual Review of Biochemistry (Impact Factor: 30.28). 02/1992; 61(1):721-59. DOI: 10.1146/
Source: PubMed
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    • "The present results are consistent with the previous work, and furthermore suggest that the kinases responsible for MRLC phosphorylation during mitosis phosphorylate Ser19 and Thr18 with same potency. We previously found that ZIPK phosphorylates MRLC at Ser19 and Thr18 with Ca 2þ independent manner [4] [23] with the same rate constant [23] and that a high concentration of ML-7 inhibits ZIPK activity [10]. We next asked whether ZIPK contributes to MRLC phosphorylation during mitosis. "
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    ABSTRACT: Zipper-interacting protein kinase (ZIPK) is known to regulate several functions such as apoptosis, smooth muscle contraction, and cell migration. While exogenously expressed GFP-ZIPK localizes to the cleavage furrow, role of ZIPK in cytokinesis is obscure. Here, we show that ZIPK is a major MRLC kinase during mitosis. Moreover, ZIPK siRNA-mediated knockdown causes delay of cytokinesis. The delay in cytokinesis of ZIPK-knockdown cells was rescued by the exogenous diphosphorylation-mimicking MRLC mutant. Taken together, these findings suggest that ZIPK plays a role in the progression and completion of cytokinesis through MRLC phosphorylation. Copyright © 2015. Published by Elsevier Inc.
    Preview · Article · Mar 2015 · Biochemical and Biophysical Research Communications
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    • "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 "

    Full-text · Article · Jan 2015 · The Journal of Physiology
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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 "
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    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.
    Full-text · Article · Jun 2014 · International review of cell and molecular biology
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