Cargo binding induces dimerization of myosin VI
Cargo binding induces dimerization of myosin VI
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DOI：
10.1073/pnas.0909748106
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发表时间：
2009-10-13
影响因子：
11.1
通讯作者：
Sweeney, H. Lee
中科院分区：
文献类型：
--
作者：
Phichith, Denis;Travaglia, Mirko;Sweeney, H. Lee
虽然肌球蛋白VI具有使其作为二聚体发挥最佳功能的特性，但全长肌球蛋白VI作为单体单独存在。基于肌球蛋白VI单体在紧密接近时二聚化的能力，我们假设货物结合通常调节肌球蛋白VI的二聚化。我们通过表达已知的肌球蛋白VI、视神经磷酸酶的二聚体货物衔接蛋白和来自单体货物衔接蛋白Dab2的肌球蛋白VI结合片段来测试这一假设。在这些衔接蛋白的存在下，全长肌球蛋白VI具有二聚体的ATP酶特性，在电子显微镜下显示为二聚体，并在肌动蛋白丝上向前移动。结果支持一种模型，其中货物结合暴露内部二聚序列内全长肌球蛋白VI。因为，出乎意料的是，Dab2的单体片段触发二聚化，似乎肌球蛋白VI被设计为在细胞中作为二聚体发挥作用。
Although myosin VI has properties that would allow it to function optimally as a dimer, full-length myosin VI exists as a monomer in isolation. Based on the ability of myosin VI monomers to dimerize when held in close proximity, we postulated that cargo binding normally regulates dimerization of myosin VI. We tested this hypothesis by expressing a known dimeric cargo adaptor protein of myosin VI, optineurin, and the myosin VI-binding segment from a monomeric cargo adaptor protein, Dab2. In the presence of these adaptor proteins, full-length myosin VI has ATPase properties of a dimer, appears as a dimer in electron micrographs, and moves processively on actin filaments. The results support a model in which cargo binding exposes internal dimerization sequences within full-length myosin VI. Because, unexpectedly, a monomeric fragment of Dab2 triggers dimerization, it would appear that myosin VI is designed to function as a dimer in cells.