Department of Cell and Molecular Biology, Northwestern University, Chicago, IL 60611, USA.
J Cell Biol. 2009 Dec 28;187(7):1071-82. doi: 10.1083/jcb.200908075.
Intracellular transport is typically bidirectional, consisting of a series of back and forth movements. Kinesin-1 and cytoplasmic dynein require each other for bidirectional transport of intracellular cargo along microtubules; i.e., inhibition or depletion of kinesin-1 abolishes dynein-driven cargo transport and vice versa. Using Drosophila melanogaster S2 cells, we demonstrate that replacement of endogenous kinesin-1 or dynein with an unrelated, peroxisome-targeted motor of the same directionality activates peroxisome transport in the opposite direction. However, motility-deficient versions of motors, which retain the ability to bind microtubules and hydrolyze adenosine triphosphate, do not activate peroxisome motility. Thus, any pair of opposite-polarity motors, provided they move along microtubules, can activate one another. These results demonstrate that mechanical interactions between opposite-polarity motors are necessary and sufficient for bidirectional organelle transport in live cells.
细胞内运输通常是双向的，由一系列往返运动组成。驱动蛋白-1 和细胞质动力蛋白相互协作，沿着微管进行细胞内货物的双向运输；即，抑制或耗尽驱动蛋白-1 会消除动力蛋白驱动的货物运输，反之亦然。使用黑腹果蝇 S2 细胞，我们证明了用同一方向的无关的过氧化物酶体靶向马达替代内源性驱动蛋白-1 或动力蛋白会激活过氧化物酶体向相反方向的运输。然而，保留结合微管和水解三磷酸腺苷能力的马达运动缺陷版本不会激活过氧化物酶体运动。因此，任何一对相反极性的马达，只要它们沿着微管运动，就可以相互激活。这些结果表明，相反极性马达之间的机械相互作用对于活细胞中双向细胞器运输是必要和充分的。
