Ion Channel Hyperactivity Needed for Egg Fertilization

Researchers studying reproduction at the level of sperm cell metabolism have found that an ion channel protein is required to maintain the state of hyperactivation that enables the sperm to penetrate the egg cell's extracellular matrix, a step that is necessary for fertilization to take place.

Investigators at the University of Texas Southwestern Medical Center (Dallas, USA) genetically engineered a line of mice lacking the gene for production of CatSper1. They reported in the December 9, 2003, online edition of the Proceedings of the [U.S.] National Academy of Sciences that CatSper1 was essential for depolarization-evoked calcium ion entry and for hyperactivated movement, a key flagellar function. CatSper1 was not needed for other developmental landmarks.

"Basically this protein or ion channel plays a critical role in sperm cell hyperactivation, which is essential for fertilization,” explained contributing author Dr. Timothy Quill, an instructor of pharmacology at the University of Texas Southwestern Medical Center. "The same protein exists in human sperm cells, so it is likely that disruption of CatSper1 would result in infertility in men as well. Blocking the protein's activity would not cause defects in the development of the sperm cell, but only prevent hyperactivation. This discovery could serve as one of the next steps in the process of creating a new type of contraceptive that would offer less risk and perform faster.”




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University of Texas Southwestern Medical Center