Researchers have now shown that the hormone acts directly on a sperm surface protein, a discovery that may suggest new nonhormonal contraceptives.
These results indicate the presence of MIF-II on sperm surface.
The quiescent state of rat spermatozoa in the distal epididymis may be dependent on a specific inhibitor protein, presumably acting at the sperm surface [6].
We here show that murine sperm possess extracellular CA IV that is transferred to the sperm surface as the sperm pass through the epididymis.
This suggests that GAGs, or molecules of similar chemical structure, are present on specific domains of the sperm surface and enable attachment of HPV16.
In accordance, ATP depletion from boar sperm surface altered the integrity of sperm proteasomes, manifested by an altered proteasomal subunit migration on SDS-PAGE [24].
This process, which involves extensive sperm surface remodelling, is required for fertilization and can be mimicked under in vitro fertilization conditions (IVF).
Plectin for its part is further able to interact with actin [62] which in spermatids is enriched within the acroplaxome and at specialized membranous junctions of spermatids and Sertoli cells at the anterior sperm surface [35], [63], [64].
Capacitation comprises a series of processes, such as modifications in sperm surface protein distribution, alterations in plasma membrane characteristics, changes in enzymatic activities and modulation of intracellular constituents [10], [11].
A post-testicular transfer of other proteins was demonstrated for sperm adhesion molecule1 (Spam1), which is secreted in epididymosomes released by the epithelial cells to the luminal fluid and integrated into the sperm surface [22], [23].
Regardless of the viability of the sperm, a transmission of the virus from the sperm surface to the female cervical epithelia could imaginably occur through simple contact between the sperm cell and the epithelia cell.
