Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan.
FEBS Lett. 2013 Jul 11;587(14):2143-9. doi: 10.1016/j.febslet.2013.05.058. Epub 2013 Jun 6.
Outer arm dynein (OAD) is bound to specific loci on outer-doublet-microtubules by interactions at two sites: via intermediate chain 1 (IC1) and the outer dynein arm docking complex (ODA-DC). Studies using Chlamydomonas mutants have suggested that the individual sites have rather weak affinities for microtubules, and therefore strong OAD attachment to microtubules is achieved by their cooperation. To test this idea, we examined interactions between IC1, IC2 (another intermediate chain) and ODA-DC using recombinant proteins. Recombinant IC1 and IC2 were found to form a 1:1 complex, and this complex associated with ODA-DC in vitro. Binding of IC1 to mutant axonemes revealed that there are specific binding sites for IC1. From these data, we propose a novel model of OAD-outer doublet association.
外臂动力蛋白（OAD）通过两个位点与外微管二联体上的特定位置相互作用结合：通过中间链 1（IC1）和外动力蛋白臂对接复合物（ODA-DC）。使用衣藻突变体的研究表明，各个位点与微管的亲和力相当弱，因此 OAD 与微管的牢固结合是通过它们的合作实现的。为了验证这一想法，我们使用重组蛋白研究了 IC1、IC2（另一种中间链）和 ODA-DC 之间的相互作用。发现重组 IC1 和 IC2 形成 1:1 复合物，并且该复合物在体外与 ODA-DC 结合。IC1 与突变轴丝的结合表明存在 IC1 的特异性结合位点。根据这些数据，我们提出了一个新的 OAD-outer doublet 关联模型。
