Chlamydomonas CAV2 Encodes a Voltage-Dependent Calcium Channel Required for the Flagellar Waveform Conversion
Chlamydomonas CAV2 Encodes a Voltage-Dependent Calcium Channel Required for the Flagellar Waveform Conversion
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DOI：
10.1016/j.cub.2008.11.068
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发表时间：
2009-01-27
期刊：
影响因子：
9.2
通讯作者：
Yoshimura, Kenjiro
中科院分区：
文献类型：
--
作者：
Fujiu, Kenta;Nakayama, Yoshitaka;Yoshimura, Kenjiro
纤毛和鞭毛可通过Ca 2+内流介导的膜兴奋变化来改变其搏动模式[1-6]。产生这种Ca 2+内流的离子通道及其细胞分布尚未确定。在这项研究中，我们分析了衣原体ppr 2突变体，它缺乏鞭毛Ca 2+电流的产生，因此具有缺陷的疏水反应[7]和机械休克反应。ppr 2在CAV 2中有一个突变，CAV 2编码电压依赖性钙通道（VDCCs）α（1）亚基的同源物。CAV 2具有四个结构域，每个结构域具有六个跨膜片段，并且在离子选择性过滤器中具有EEEE位点，这是脊椎动物中典型的VDCC。有趣的是，我们发现CAV 2主要定位于鞭毛的远端部分。我们提供的证据表明，CAV 2是通过鞭毛内运输（IFT）向鞭毛尖端运输，因为当IFT被阻断时，CAV 2聚集在鞭毛基部附近。本研究结果表明，衣原体鞭毛的Ca 2+内流是由VDCC，CAV 2介导的，其分布偏向于鞭毛的远端区域。
Cilia and flagella can alter their beating patterns through changes in membrane excitation mediated by Ca2+ influx [1-6]. The ion channel that generates this Ca2+ influx and its cellular distribution have not been identified. In this study, we analyzed the Chlamydomonas ppr2 mutant, which is deficient in the production of a flagellar Ca2+ current and consequently has a defective photophobic response [7] and mechanoshock response. ppr2 had a mutation in CAV2, which encodes a homolog of the alpha(1) subunit of voltage-dependent calcium channels (VDCCs). CAV2 has four domains, each with six transmembrane segments and EEEE loci in the ion-selective filter, which are typical of VDCCs in vertebrates. Interestingly, we found that CAV2 primarily localized toward the distal part of flagella. We provide evidence that CAV2 is transported toward the flagellar tip via intraflagellar transport (IFT) because CAV2 accumulated near the flagellar base when IFT was blocked. The results of this study suggest that the Ca2+ influx of Chlamydomonas flagella is mediated by the VDCC, CAV2, whose distribution is biased to the distal region of the flagellum.