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Article

  • The EMBO Journal (2005) 24, 2741 - 2752
  • doi:10.1038/sj.emboj.7600744

Published online: 7 July 2005

Ca2+ spikes in the flagellum control chemotactic behavior of sperm

Martin Böhmer1,a, Qui Van1,a, Ingo Weyand1, Volker Hagen2, Michael Beyermann2, Midori Matsumoto3, Motonori Hoshi3, Eilo Hildebrand1 and Ulrich Benjamin Kaupp1

  1. Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Jülich, Germany
  2. Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
  3. Center for Life Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Japan

Correspondence to:

Ulrich Benjamin Kaupp, Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, 52425 Jülich, Germany. Tel.: +49 2461 614041; Fax: +49 2461 614216; E-mail: a.eckert@fz-juelich.de

aThese authors contributed equally to this work

Received 15 April 2005; Accepted 16 June 2005

The events that occur during chemotaxis of sperm are only partly known. As an essential step toward determining the underlying mechanism, we have recorded Ca2+ dynamics in swimming sperm of marine invertebrates. Stimulation of the sea urchin Arbacia punctulata by the chemoattractant or by intracellular cGMP evokes Ca2+ spikes in the flagellum. A Ca2+ spike elicits a turn in the trajectory followed by a period of straight swimming ('turn-and-run'). The train of Ca2+ spikes gives rise to repetitive loop-like movements. When sperm swim in a concentration gradient of the attractant, the Ca2+ spikes and the stimulus function are synchronized, suggesting that precise timing of Ca2+ spikes controls navigation. We identified the peptide asterosap as a chemotactic factor of the starfish Asterias amurensis. The Ca2+ spikes and swimming behavior of sperm from starfish and sea urchin are similar, implying that the signaling pathway of chemotaxis has been conserved for almost 500 million years.

  • Keywords:

    • cyclic nucleotides,
    • sea urchin,
    • signaling,
    • sperm-activating peptides,
    • starfish