Ca2+ spikes in the flagellum control chemotactic behavior of sperm

Martin Böhmer, Qui Van, Ingo Weyand, Volker Hagen, Michael Beyermann, Midori Matsumoto, Motonori Hoshi, Eilo Hildebrand, Ulrich Benjamin Kaupp

Research output: Contribution to journalArticlepeer-review

158 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2741-2752
Number of pages12
JournalEMBO Journal
Issue number15
Publication statusPublished - 2005 Aug 3


  • Cyclic nucleotides
  • Sea urchin
  • Signaling
  • Sperm-activating peptides
  • Starfish

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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