Yokota E, Mabuchi I
Department of Biology, College of Arts and Sciences, University of Tokyo, Japan.
Eur J Cell Biol. 1997 Mar;72(3):214-21.
We have isolated C/A dynein, which is considered to be a component of inner arms, from flagellar axonemes of sea urchin sperm (E. Yokota, I. Mabuchi, J. Cell Sci. 107, 345-351 (1994). C/A dynein binds to and bundles the microtubules in the absence of ATP. In contrast to outer arm 21S dynein, C/A dynein is not released from the microtubules in the presence of ATP (E. Yokota, I. Mabuchi, J. Cell Sci. 107, 353-361 (1994)). We further investigated the interaction of C/A dynein with microtubules in the presence of ATP. The turbidity at 350 nm of a mixture of C/A dynein and microtubules increased by the addition of ATP. Both the initial rate and final extent of the turbidity increase were dependent on C/A dynein or ATP concentration and were inhibited by vanadate. ATP hydrolysis by C/A dynein was linear during the time course of the turbidity increase. Negative staining electron microscopy revealed that microtubular bundles which formed in the presence of C/A dynein became thicker and longer after addition of ATP. Furthermore, sliding movements of microtubule(s) in the individual bundles were observed in the presence of ATP. This mode of interaction of C/A dynein with microtubules was distinct from that of flagellar or ciliary dyneins reported so far. These results suggest that C/A dynein, as a component of inner arms, may play a distinct role in the flagellar movement of sea urchin sperm.
我们从海胆精子的鞭毛轴丝中分离出了C/A动力蛋白，它被认为是内臂的一个组成部分（E. 横田、今渊 伊织，《细胞科学杂志》107卷，345 - 351页（1994年））。C/A动力蛋白在没有ATP的情况下能结合并使微管成束。与外臂21S动力蛋白不同，C/A动力蛋白在有ATP存在时不会从微管上释放下来（E. 横田、今渊 伊织，《细胞科学杂志》107卷，353 - 361页（1994年））。我们进一步研究了在有ATP存在时C/A动力蛋白与微管的相互作用。加入ATP后，C/A动力蛋白和微管混合物在350nm处的浊度增加。浊度增加的初始速率和最终程度都取决于C/A动力蛋白或ATP的浓度，并受到钒酸盐的抑制。在浊度增加的时间过程中，C/A动力蛋白的ATP水解呈线性。负染电子显微镜显示，在加入ATP后，由C/A动力蛋白形成的微管束变得更厚更长。此外，在有ATP存在时，观察到单个微管束中微管的滑动运动。C/A动力蛋白与微管的这种相互作用模式与迄今为止报道的鞭毛或纤毛动力蛋白的相互作用模式不同。这些结果表明，作为内臂的一个组成部分，C/A动力蛋白可能在海胆精子的鞭毛运动中发挥独特作用。
