Effects of the regulatory light chain phosphorylation of myosin II on mitosis and cytokinesis of mammalian cells
Department of Physiology
Animals; *Cell Cycle; Cell Division; Cell Line; Cells, Cultured; Green Fluorescent Proteins; Luminescent Proteins; Myosins; Phosphorylation; Recombinant Fusion Proteins
Biochemistry, Biophysics, and Structural Biology | Cellular and Molecular Physiology | Life Sciences | Medicine and Health Sciences
Myosin plays an important role in mitosis, especially during cytokinesis. Although it has been assumed that phosphorylation of regulatory light chain of myosin (RLC) controls motility of mammalian non-muscle cells, the functional significance of RLC phosphorylation remains uninvestigated. To address this problem, we have produced unphosphorylatable RLC (T18A/S19A RLC) and overexpressed it in COS-7 cells and normal rat kidney cells. Overexpression of T18A/S19A RLC but not wild type RLC almost completely abolished concanavalin A-induced receptor cap formation. The results indicate that myosin phosphorylation is critical for concanavalin A-induced gathering of surface receptors. T18A/S19A RLC overexpression resulted in the production of multinucleated cells, suggesting the failure of proper cell division in these cells. Video microscopic observation revealed that cells expressing T18A/S19A RLC showed abnormalities during mitosis in two respects. One is that the cells produced abnormal cleavage furrows, resulting in incomplete cytokinesis, which suggests that myosin phosphorylation is important for the normal recruitment of myosin molecules into the contractile ring structure. The other is that separation of chromosomes from the metaphase plate is disrupted in T18A/S19A RLC expressing cells, thus preventing proper transition from metaphase to anaphase. These results suggest that, in addition to cytokinesis, myosin and myosin phosphorylation play a role in the karyokinetic process.
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Citation: J Biol Chem. 2000 Nov 3;275(44):34512-20. Link to article on publisher's site
DOI of Published Version
The Journal of biological chemistry
Komatsu, Satoshi; Yano, Takeo; Shibata, Masao; Tuft, Richard A.; and Ikebe, Mitsuo, "Effects of the regulatory light chain phosphorylation of myosin II on mitosis and cytokinesis of mammalian cells" (2000). Open Access Articles. 752.