Real-time analysis of the role of Ca2+ in flagellar movement and motility in single sea urchin sperm
Real-time analysis of the role of Ca2+ in flagellar movement and motility in single sea urchin sperm
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DOI：
10.1083/jcb.200411001
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发表时间：
2005-06-06
影响因子：
7.8
通讯作者：
Darszon, A
中科院分区：
文献类型：
--
作者：
Wood, CD;Nisihigaki, T;Darszon, A
许多海洋和哺乳动物的卵子通过释放化学引诱剂来吸引精子，这些化学引诱剂可以改变鞭毛的弯曲特性，使精子的路径转向卵子。这一过程被称为趋化性，依赖于细胞外Ca2+。我们使用频闪荧光成像测量游动海胆精子鞭毛细胞内Ca2+浓度（[Ca2+]i）。环状GMP通过至少两种不同的途径诱导Ca2+进入，我们确定了鞭毛中尼莫地平敏感的途径，作为鞭毛弯曲和定向运动变化的关键调节剂。我们发现，与目前的模型相反，鞭毛弯曲的程度并不与整体[Ca2+]i成比例。相反，我们提出了一种新的模型，即鞭毛弯曲通过尼莫地平敏感途径通过Ca2+通量增加，并且通过替代途径不受[Ca2+]i增加的影响。
Eggs of many marine and mammalian species attract sperm by releasing chemoattractants that modify the bending properties of flagella to redirect sperm paths toward the egg. This process, called chemotaxis, is dependent on extracellular Ca2+. We used stroboscopic fluorescence imaging to measure intracellular Ca2+ concentration ([Ca2+]i) in the flagella of swimming sea urchin sperm. Uncaging of cyclic GMP induced Ca2+ entry via at least two distinct pathways, and we identified a nimodipine-sensitive pathway, compartmentalized in the flagella, as a key regulator of flagellar bending and directed motility changes. We found that, contrary to current models, the degree of flagellar bending does not vary in proportion to the overall [Ca2+]i. Instead we propose a new model whereby flagella bending is increased by Ca2+ flux through the nimodipine-sensitive pathway, and is unaffected by [Ca2+]i increases through alternative pathways.