How sperm find their way
UTokyo researchers continue to unravel the mystery of how the male reproductive cell navigates
Overview of the press release
Professor Manabu Yoshida from the Misaki Marine Biological Station at the University of Tokyo and colleagues have found that a protein in the cell membranes of sperm plays a key role in how they find their way to eggs. The PMCA protein may also help explain how egg cells only interact with sperm from the same species. PMCA may even be a target of drug discovery.
Sperm cells, bacteria and other microscopic organisms use varying concentrations of chemicals in their environment - concentration gradients - to approach or avoid something in a process called chemotaxis. Egg cells release an attractant chemical, which lures the sperm. The researchers studied this action in Ascidia - sea squirts, brainless tubular creatures, which are only mobile as larvae.
"We identified that a calcium transport protein - plasma membrane Ca2+ ATPase (PMCA) - has a key role in sperm chemotaxis," says Yoshida. "PMCA is abundant in the tails or flagella membranes of the ascidian sperm. It binds to the species-specific attractant and alters how the flagella waves, thus directing movement of the sperm cell."
Figure: PMCA and SAAF cell signalling pathway
This figure depicts how University of Tokyo researchers believe sperm cells navigate thanks to PMCA (plasma membrane Ca2+ ATPase) and SAAF (sperm activating and attracting factor).
The finding was published in Scientific Reports.
― Office of Communication ―