Scientists have solved a 20-year mystery regarding the molecular mechanism by which human sperm detect an egg. The answer lies in a unique ion channel that senses progesterone, causing an influx of calcium into the sperm cells. The finding, published in a pair of papers this week in linkurl:Nature,; provides a clue to some types of male infertility, and could someday be the foundation for a non-hormonal contraceptive.
Illustration by linkurl:Carin Cain;
"It's a real step forward," said linkurl:Steve Publicover,; who studies human sperm at the University of Birmingham in the UK and was not involved in the research. "It gives us a handle on what is going on in sperm." Prior to fertilization, a cloud of cumulus cells surrounding the egg release progesterone, the female sex hormone, triggering a calcium influx into the sperm. This flood of calcium causes the sperm to beat their flagella rapidly, an...
News & ViewsNature. Strunker, T., et al., "The CatSper channel mediates progesterone-induced Ca2+ influx in human sperm," Nature, 471:382-6. Lishko, P.V., et al., "Progesterone activates the principal Ca2+ channel of human sperm," Nature, 471:387-91, 2011.

J Biol Chem,

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