King S J, Schroer T A
Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Nat Cell Biol. 2000 Jan;2(1):20-4. doi: 10.1038/71338.
Cytoplasmic dynein supports long-range intracellular movements of cargo in vivo but does not appear to be a processive motor protein by itself. We show here that the dynein activator, dynactin, binds microtubules and increases the average length of cytoplasmic-dynein-driven movements without affecting the velocity or microtubule-stimulated ATPase kinetics of cytoplasmic dynein. Enhancement of microtubule binding and motility by dynactin are both inhibited by an antibody to dynactin's microtubule-binding domain. These results indicate that dynactin acts as a processivity factor for cytoplasmic-dynein-based motility and provide the first evidence that cytoskeletal motor processivity can be affected by extrinsic factors.
胞质动力蛋白在体内支持货物的长距离细胞内运输，但它本身似乎不是一种持续性运动蛋白。我们在此表明，动力蛋白激活剂动力肌动蛋白结合微管，并增加胞质动力蛋白驱动运动的平均长度，而不影响胞质动力蛋白的速度或微管刺激的ATP酶动力学。针对动力肌动蛋白微管结合结构域的抗体可抑制动力肌动蛋白对微管结合和运动性的增强作用。这些结果表明，动力肌动蛋白作为基于胞质动力蛋白运动的持续性因子，首次证明细胞骨架运动的持续性可受外在因素影响。
