Fertilization is the union of two cells: an egg and a sperm. Before the egg and the sperm fuse, an event known as the “acrosome reaction” needs to occur in the sperm. Now, a team from Osaka University in Japan has identified a protein called FER1L5 that is essential for sperm to undergo the acrosome reaction.
There is a cap-like vesicle structure called the acrosome over the front of the head of a sperm. As the sperm migrates in the female reproductive tract in mammals, the acrosome reaction occurs, which involves the release of molecules in the acrosome to facilitate fertilization. Although the acrosome reaction is essential for sperm to fertilize eggs, the mechanism that regulates the acrosome reaction remains unclear.
The research team examined six ferlin family proteins in both roundworms and mice. “Our results indicate that the function of ferlin proteins is well conserved from nematodes to mice, although their sperm look different,” explains senior author Masahito Ikawa. While this study was carried out on mice, FER1L5 protein is known to be present in human sperm. Further research resulting from this study may therefore lead to new treatments and diagnostic methods for male infertility in humans.
The article is published in Science Advances.