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Updated: Jul 11, 2026

Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays
Published on: February 4, 2021
Characterization of native myosin VI isolated from sea urchin eggs
Souhei Sakata1, Yuuko Watanabe, Jiro Usukura
1Division of Biology, Department of Life Sciences, Graduate School of Arts and Science, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Abstract:
Myosin VI is a molecular motor that is ubiquitously expressed among eukaryotic cells, and thought to be involved in membrane trafficking and anchoring the organelle to actin cytoskeleton. Studies on myosin VI have been carried out using recombinant proteins, but native myosin VI has not been purified yet. Here we purified native myosin VI from sea urchin eggs and characterized its properties. We found that the native myosin VI was a monomeric and non-processive motor protein, and also showed that it moved toward the pointed end of F-actin. Ca2+ stimulated actin-activated MgATPase activity of the native myosin VI, while it lowered its motility on F-actin. Immunofluorescence microscopy showed that the myosin VI was translocated from the inner cytoplasm to the cortex after fertilization. Myosin VI may be involved in endocytic activities in fertilized eggs.
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