Researchers Identify Molecule Needed for Sperm Activation

Researchers have found the cellular switch that boosts activity of sperm cells so they can travel to the egg.

Photo: Carin Cain

Researchers funded by NIH have discovered the cellular switch that boosts the activity of sperm cells so that they can travel to the egg. The finding may lead to new options for male contraception as well as treatments for infertility resulting from problems with sperm mobility.

Inside the male reproductive tract, mature sperm are capable of limited movement. This limited movement, however, is not enough to propel them toward the egg when they enter the female reproductive tract. To begin their journey, they must first be activated by the hormone progesterone, which is released by the egg.

Publishing online in Science, the researchers report that the molecule to which progesterone must bind is the enzyme alpha/beta hydrolase domain containing protein 2 (ABHD2), found in the sperm cell’s outer membrane. The study was conducted by Dr. Melissa R. Miller and colleagues at the University of California, Berkeley; the University of California, San Francisco; and Yale University School of Medicine.

“This is an important advance in explaining how sperm become hypermotile in the female reproductive tract,” said Dr. Stuart Moss, director of the male reproductive health program at NICHD, which funded the study. “Developing new compounds that block ABHD2 ultimately may yield new contraceptive methods to prevent sperm from reaching the egg.”