PDF(Pubmed)
Abstract：
Calcium is critical for regulating the waveform of motile cilia and flagella. Calaxin is currently the only known molecule involved in the calcium-dependent regulation in ascidians. We have recently shown that Calaxin stabilizes outer arm dynein (OAD), and the knockout of Calaxin results in primary ciliary dyskinesia phenotypes in vertebrates. However, from the knockout experiments, it was not clear which functions depend on calcium and how Calaxin regulates the waveform. To address this question, here, we generated transgenic zebrafish expressing a mutant E130A-Calaxin deficient in calcium binding. E130A-Calaxin restored the OAD reduction of calaxin -/- sperm and the abnormal movement of calaxin -/- left-right organizer cilia, showing that Calaxin\'s stabilization of OADs is calcium-independent. In contrast, our quantitative analysis of E130A-Calaxin sperms showed that the calcium-induced asymmetric beating was not restored, linking Calaxin\'s calcium-binding ability with an asymmetric flagellar beating for the first time. Our data show that Calaxin is a calcium-dependent regulator of the ciliary beating and a calcium-independent OAD stabilizer.
摘要：
钙对于调节活动纤毛和鞭毛的波形至关重要。Calaxin是目前唯一已知的参与海鞘中钙依赖性调节的分子。我们最近发现Calaxin能稳定外臂动力蛋白（OAD），Calaxin的敲除导致脊椎动物的原发性纤毛运动障碍表型。然而,从淘汰赛实验中，尚不清楚哪些功能取决于钙以及Calaxin如何调节波形。为了解决这个问题，在这里，我们产生了表达缺乏钙结合的突变体E130A-Calaxin的转基因斑马鱼。E130A-Calaxin恢复了calaxin-/-精子的OAD减少和calaxin-/-左右组织者纤毛的异常运动，表明Calaxin对OAD的稳定是不依赖钙的。相比之下,我们对E130A-Calaxin精子的定量分析表明，钙诱导的不对称搏动没有恢复，首次将Calaxin的钙结合能力与不对称鞭毛搏动联系起来。我们的数据表明，Calaxin是纤毛搏动的钙依赖性调节剂和钙非依赖性OAD稳定剂。
