Unique Sperm Protein A Possible Contraceptive Target.(CatSper ion channel could be target for contraceptive that could be taken by men or women)

2001 NOV 8 - (NewsRx.com & NewsRx.net) -- An ion channel protein that plays a central role in sperm motility could be an enticing target for a new type of contraceptive that could be taken by either men or women to block fertilization.

The newly discovered protein, called CatSper, controls the flow of calcium into the tails of spermatozoa. This influx of calcium triggers the sperm's motor proteins, causing the tail to beat.

The CatSper ion channel is found only in a principal section of the sperm's tail and nowhere else in the body, making it likely that a contraceptive that targets CatSper would have far fewer side effects than a hormone-based contraceptive.

Discovery of the CatSper ion channel was reported in an article published in the October 11, 2001, issue of the journal Nature by Howard Hughes Medical Institute investigator David E. Clapham and colleagues at Harvard Medical School.

"It has been known that there are ion channels in sperm," said Clapham. "But most of the ion channels studied before were associated with the sperm head."

According to Clapham, these ion channels govern processes such as the sperm's ability to dissolve the thick outer coating of the egg. "While people would have expected ion channels to exist in the tail, they are extremely hard to measure," he said.

Clapham and his colleagues were performing a general screen of the human gene database for novel calcium-selective ion channel genes when they discovered one with an unusual structure that resembled other channels known to play a role in cell motility.