Globozoospermia is a rare but severe male infertility disorder. Jun Xia and colleagues, at The Hong Kong University of Science and Technology, People's Republic of China, have now discovered that male mice lacking the protein PICK1 are infertile and that their condition resembles men with globozoospermia, potentially shedding light on this human disorder.
In the study, male mice were found to have a low sperm count, with the remaining sperm looking abnormal (they had round heads) and being severely impaired in their ability to move. Further analysis revealed that compartments in the sperm known as acrosomes, which contain proteins that breakdown the outer membrane of the egg so that a sperm can enter for fertilization to occur, were malformed.
As PICK1 was shown to interact with two proteins (GOPC and CK2-alpha') in the vicinity of cellular structures that form acrosomes, the authors suggest that PICK1 has an essential role in acrosome formation.