Myosin-Va Regulates Exocytosis through the Submicromolar Ca<sup>2</sup>+-dependent Binding of Syntaxin-1A
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- Michitoshi Watanabe
- Division of Molecular and Cellular Biology, Niigata University, Niigata, Niigata 951-8510, Japan
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- Kazushige Nomura
- Division of Molecular and Cellular Biology, Niigata University, Niigata, Niigata 951-8510, Japan
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- Akihiro Ohyama
- Department of Molecular and Cellular Neurobiology, Gunma University School of Medicine, Maebashi, Gunma 371-8511, Japan
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- Ryoki Ishikawa
- Department of Molecular and Cellular Pharmacology, Gunma University School of Medicine, Maebashi, Gunma 371-8511, Japan
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- Yoshiaki Komiya
- Department of Molecular and Cellular Neurobiology, Gunma University School of Medicine, Maebashi, Gunma 371-8511, Japan
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- Kohei Hosaka
- Basic Sciences for Medicine, Gunma University School of Health Sciences, Maebashi, Gunma 371-8514, Japan
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- Emiko Yamauchi
- Division of Enzyme Physiology, Institute for Enzyme Research, University of Tokushima, Tokushima, Tokushima 770-8503, Japan
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- Hisaaki Taniguchi
- Division of Enzyme Physiology, Institute for Enzyme Research, University of Tokushima, Tokushima, Tokushima 770-8503, Japan
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- Nobuyuki Sasakawa
- Life Science Institute, Sophia University, Chiyoda-ku, Tokyo 102-8554, Japan
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- Konosuke Kumakura
- Life Science Institute, Sophia University, Chiyoda-ku, Tokyo 102-8554, Japan
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- Tatsuo Ushiki
- Division of Microscopic Anatomy and Bio-Imaging, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Niigata 951-8510, Japan
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- Osamu Sato
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655-0127
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- Mitsuo Ikebe
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655-0127
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- Michihiro Igarashi
- Division of Molecular and Cellular Biology, Niigata University, Niigata, Niigata 951-8510, Japan
抄録
<jats:p>Myosin-Va is an actin-based processive motor that conveys intracellular cargoes. Synaptic vesicles are one of the most important cargoes for myosin-Va, but the role of mammalian myosin-Va in secretion is less clear than for its yeast homologue, Myo2p. In the current studies, we show that myosin-Va on synaptic vesicles interacts with syntaxin-1A, a t-SNARE involved in exocytosis, at or above 0.3 μM Ca<jats:sup>2+</jats:sup>. Interference with formation of the syntaxin-1A–myosin–Va complex reduces the exocytotic frequency in chromaffin cells. Surprisingly, the syntaxin-1A-binding site was not in the tail of myosin-Va but rather in the neck, a region that contains calmodulin-binding IQ-motifs. Furthermore, we found that syntaxin-1A binding by myosin-Va in the presence of Ca<jats:sup>2+</jats:sup>depends on the release of calmodulin from the myosin-Va neck, allowing syntaxin-1A to occupy the vacant IQ-motif. Using an anti-myosin-Va neck antibody, which blocks this binding, we demonstrated that the step most important for the antibody's inhibitory activity is the late sustained phase, which is involved in supplying readily releasable vesicles. Our results demonstrate that the interaction between myosin-Va and syntaxin-1A is involved in exocytosis and suggest that the myosin-Va neck contributes not only to the large step size but also to the regulation of exocytosis by Ca<jats:sup>2+</jats:sup>.</jats:p>
収録刊行物
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- Molecular Biology of the Cell
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Molecular Biology of the Cell 16 (10), 4519-4530, 2005-10
American Society for Cell Biology (ASCB)
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詳細情報
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- CRID
- 1364233271200564352
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- NII論文ID
- 30018380157
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- ISSN
- 19394586
- 10591524
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- データソース種別
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