DYNEIN BINDS TO AND CROSSBRIDGES CYTOPLASMIC MICROTUBULES
DYNEIN BINDS TO AND CROSSBRIDGES CYTOPLASMIC MICROTUBULES
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DOI：
10.1073/pnas.76.11.5759
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
ROSENBAUM, JL
中科院分区：
文献类型：
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作者：
HAIMO, LT;TELZER, BR;ROSENBAUM, JL
从莱茵衣藻鞭毛轴丝中分离出的动力蛋白与6S脑微管蛋白二聚体在体外组装的微管结合。动力蛋白臂沿着微管的长度周期性地结合，中心到中心的间距为24 nm，相当于完整轴丝上动力蛋白臂的周期。臂从体外组装的微管以大约55度的角度突出，从而定义了微管的极性。EM、凝胶电泳和ATPase分析表明，动力蛋白通过蔗糖梯度与微管共聚体。此外，动力蛋白还能诱导相邻微管之间的交叉桥。暗视野显微镜显示，含有动力蛋白的微管聚集成大束；EM表明，相同极性的微管被规则的手臂阵列交叉连接。在暗视野显微镜下观察，加入三磷酸腺苷可引起交叉桥微管的解聚；EM显示大多数交叉桥微管不再是交桥微管。这些观察结果可用于确定微管的极性和微管原位组装的方向性，并提示动力蛋白在基于细胞质微管的细胞运动中的作用。
Dynein isolated from Chlamydomonas reinhardtii flagellar axonemes binds to microtubules assembled in vitro from 6S brain tubulin dimers. The dynein arms bind periodically along the length of the microtubules with a center-to-center spacing of 24 nm, equal to the periodicity of dynein arms on intact axonemes. The arms project from the in vitro assembled microtubules at an angle of approximately 55.degree., thereby defining microtubule polarity. Dynein cosediments with microtubules through a sucrose gradient, as demonstrated by EM, gel electrophoresis, and ATPase analysis. In addition, dynein induces crossbridging between adjacent microtubules. Darkfield microscopy reveals that microtubules containing dynein are aggregated into large bundles; EM indicates that microtubules of the same polarity are crossbridged by a regular array of arms. Viewed by darkfield microscopy, addition of ATP to crossbridged microtubules causes their disaggregation; EM shows that the majority of these microtubules are no longer crossbridged. These observations are applicable to the determination of microtubule polarity and directionality of microtubule assembly in situ and suggest a role for dynein in cytoplasmic microtubule-based cellular movements.