The proximal segment of the epididymis responds to the switch factor NELL2 and synthesizes OVCH2 (magenta), a protein indispensable for sperm maturation. Credit: Osaka University For a sperm to fertilize an egg, the sperm must first mature in a man’s epididymis. Now, an international team of researchers has identified a chain of events in which a protein secreted by the testis travels in the luminal fluid, binds to a receptor on the epididymis to induce its differentiation and secretion of a second protein that matures the sperm and enables each sperm to be motile in females.
In a new study published in Science , researchers from Osaka University and Baylor College of Medicine have identified NELL2, a secreted protein factor that acts on the epididymis through this novel lumicrine pathway to mediate sperm maturation.
Sperm are produced in the seminiferous tubules of the testis and transit through the epididymis, a long, convoluted tube linked to the vas deferens. When the sperm enter the epididymis, they are not motile and are incapable of fertilization; however, in their passage through the epididymis, the sperm are provided an appropriate environment for maturation and storage pending ejaculation.
It has been hypothesized that proteins released by the […]
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