Brain myosin V is a synaptic vesicle-associated motor protein: evidence for a Ca2+-dependent interaction with the synaptobrevin-synaptophysin complex.
Brain myosin V is a synaptic vesicle-associated motor protein: evidence for a Ca2+-dependent interaction with the synaptobrevin-synaptophysin complex.
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DOI：
10.1083/jcb.137.7.1589
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发表时间：
1997-06-30
期刊：
影响因子：
--
通讯作者：
Terrian DM
中科院分区：
文献类型：
--
作者：
Prekeris R;Terrian DM
脑肌球蛋白V是一类广泛分布的非常规肌球蛋白的成员，可能是所有真核细胞中细胞器运输的核心重要性。将这种分子马达靶向细胞器的分子成分先前尚未被鉴定。使用免疫纯化，提取，交联和共沉淀试验的组合，我们证明，脑肌球蛋白V的尾部结构域形成一个稳定的复合物与突触囊泡膜蛋白，小突触蛋白II和突触素。虽然肌球蛋白V主要是结合在休息时的突触囊泡，这个假定的运输复合物迅速解体后，去极化诱导的Ca 2+进入完整的神经末梢。免疫共沉淀试验进一步表明，Ca 2+破坏在体外结合的小突触素II的存在下，但不是在Mg 2+的情况下，突触素。我们的结论是，亲水力可逆耦合肌球蛋白V尾生化定义类细胞器在脑神经末梢。
Brain myosin V is a member of a widely distributed class of unconventional myosins that may be of central importance to organelle trafficking in all eukaryotic cells. Molecular constituents that target this molecular motor to organelles have not been previously identified. Using a combination of immunopurification, extraction, cross-linking, and coprecipitation assays, we demonstrate that the tail domain of brain myosin V forms a stable complex with the synaptic vesicle membrane proteins, synaptobrevin II and synaptophysin. While myosin V was principally bound to synaptic vesicles during rest, this putative transport complex was promptly disassembled upon the depolarization-induced entry of Ca2+ into intact nerve endings. Coimmunoprecipitation assays further indicate that Ca2+ disrupts the in vitro binding of synaptobrevin II to synaptophysin in the presence but not in the absence of Mg2+. We conclude that hydrophilic forces reversibly couple the myosin V tail to a biochemically defined class of organelles in brain nerve terminals.