Two key proteins for male fertility identified

Two key proteins for sperm development have been identified. Their absence or dysfunction has significant consequences for male fertility . Called Cfap91 and Efcab5 , they control the movement of the sperm's "tail ," the flagellum . The discovery, published in the journal Nature Communications by a team of researchers from Osaka University in Japan, opens the door to more accurate diagnoses of male infertility and even potential new treatments .

The flagellum is the structure that allows sperm to move. If the flagella don't work properly, sperm travel inefficiently and, consequently, have a lower chance of achieving pregnancy. However, this tail has a rather complicated structure, so it's not easy to understand how a protein alters its motility.

"The structure of the sperm flagellum is quite complex ," says Haoting Wang, who led the researchers, "and also includes radial spokes, which are essential for controlling flagellar movement. Cfap91 was known to be implicated in human male infertility," adds Wang, "but it was unclear why."

To understand the role of this protein, the study authors genetically engineered mice to lack Cfap91. "Our results," Wang states, "demonstrate that Cfap91 influences male fertility because it acts as a scaffold for the assembly of radial spokes." By analyzing this protein, the researchers also identified another, Efcab5 , which interacts with the first and is essential for controlling sperm movement.