Characterization of Ring-Like F-Actin Structure as a Mechanical Partner for Spindle Positioning in Mitosis |
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Authors: | Huan Lu Qun Zhao Hao Jiang Tongge Zhu Peng Xia William Seffens Felix Aikhionbare Dongmei Wang Zhen Dou Xuebiao Yao |
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Institution: | 1. Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China.; 2. Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, United States of America.; Georgia Regents University, United States of America, |
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Abstract: | Proper spindle positioning and orientation are essential for accurate mitosis which requires dynamic interactions between microtubule and actin filament (F-actin). Although mounting evidence demonstrates the role of F-actin in cortical cytoskeleton dynamics, it remains elusive as to the structure and function of F-actin-based networks in spindle geometry. Here we showed a ring-like F-actin structure surrounding the mitotic spindle which forms since metaphase and maintains in MG132-arrested metaphase HeLa cells. This cytoplasmic F-actin structure is relatively isotropic and less dynamic. Our computational modeling of spindle position process suggests a possible mechanism by which the ring-like F-actin structure can regulate astral microtubule dynamics and thus mitotic spindle orientation. We further demonstrated that inhibiting Plk1, Mps1 or Myosin, and disruption of microtubules or F-actin polymerization perturbs the formation of the ring-like F-actin structure and alters spindle position and symmetric division. These findings reveal a previously unrecognized but important link between mitotic spindle and ring-like F-actin network in accurate mitosis and enables the development of a method to theoretically illustrate the relationship between mitotic spindle and cytoplasmic F-actin. |
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