Bending-Induced Switching of Dynein Activity in Elastase-Treated Axonemes of Sea Urchin Sperm-Roles of Ca2+ and ADP
Bending-Induced Switching of Dynein Activity in Elastase-Treated Axonemes of Sea Urchin Sperm-Roles of Ca2+ and ADP
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DOI：
10.1002/cm.20360
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发表时间：
2009-05-01
影响因子：
--
通讯作者：
Shingyoji, Chikako
中科院分区：
文献类型：
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作者：
Hayashi, Shuichi;Shingyoji, Chikako
鞭毛跳动是由微管滑动引起的，由动力蛋白的活性驱动，在九个双微管中相邻的两个之间。动力蛋白调节的一个重要过程是在中央微管对的两侧之间交替其活性（转换）。动力蛋白活性的转换，可以检测到，在体外系统中使用弹性蛋白酶处理的海胆精子鞭毛的轴丝，在高Ca 2+，（10（-4）M）在pH 7.9-8.0的两束双联体之间的ATP诱导的滑动的相对方向的逆转。这种反转是由偶极束的外加弯曲触发的。然而，这种弯曲引起的逆转（或向后滑动）的机制仍不清楚。为了了解如何在鞭毛中的动力蛋白活性的开关可以通过弯曲诱导，我们研究了ADP的作用，这是一个重要因素的动力蛋白运动活性，和Ca 2+的弯曲诱导逆转微管之间的两束双峰在pH 7.5和7.2滑动。结果表明，在低pH条件下，无论Ca ~（2+）浓度如何，都能引起滑动方向的逆转，但在低Ca ~（2+）（< 10 ~（-9）M）条件下比在高Ca ~（2+）条件下发生得更频繁。在pH 7.5时，ADP的应用增加了在高浓度和低浓度的Ca 2+时向后滑动的发生频率。结果表明，ADP依赖的动力蛋白激活，可能是由于ADP结合到动力蛋白，参与调节弯曲诱导的鞭毛动力蛋白活性转换。细胞动力。Cytoskeleton 66：292-301，2009. (C)2009威利-利斯公司
Flagellar beating is caused by microtubule sliding, driven by the activity of dynein, between adjacent two of the nine doublet microtubules. An essential process in the regulation of dynein is to alternate its activity (switching) between the two sides of the central pair microtubules. The switching of dynein activity can be detected, in an in vitro system using elastase-treated axonemes of sea urchin sperm flagella, as a reversal of the relative direction of ATP-induced sliding between the two bundles of doublets at high Ca2+, (10(-4) M) at pH 7.9-8.0. The reversal is triggered by externally applied bending of the doublet bundle. However, the mechanism of this bending-induced reversal (or backward sliding) remains unclear. To understand how the switching of dynein activity in flagella can be induced by bending, we studied the roles of ADP, which is an important factor for the dynein motile activity, and of Ca2+ in the bending-induced reversal of microtubule sliding between two bundles of doublets at pH 7.5 and 7.2. We found that the reversal of sliding direction was induced regardless of the concentrations of Ca2+ at low pH, but occurred more frequently at low Ca2+ (< 10(-9) M) than at high Ca2+. At pH 7.5, an application of ADP increased the frequency of occurrence of backward sliding at high as well as low concentrations of Ca2+. The results indicate that ADP-dependent activation of dynein, probably resulting from ADP-binding to dynein, is involved in the regulation of the bending-induced switching of dynein activity in flagella. Cell Motil. Cytoskeleton 66: 292-301, 2009. (C) 2009 Wiley-Liss, Inc.