UVA researcher Young-Hwan Kim has discovered a protein in sperm tails that may be crucial for the development of male contraceptive drugs. Known as SFEC (sperm flagellar energy carrier), this protein helps sperm use energy; disrupting it could stop sperm from swimming, hence the contraception connection.

Unlike previously explored sperm proteins, SFEC is located in the tail of the sperm, so is closely linked with the process of glycolysis, whereby sperm consume and produce energy for movement. “In experiments where glycolysis was blocked, the sperm barely quivered, showed no progressive motion and were infertile,” says Kim. Drugs that can bind to the SFEC protein and disrupt its functioning could thus be used as male contraceptives in the near future.

Published in Developmental Biology, Kim’s research was performed in the laboratory of John Herr, who heads UVA’s Center for Research in Contraceptive and Reproductive Health. In their quest for a male contraceptive, Herr’s team has been searching for proteins that would work as target sites for small-molecule drugs. Kim’s discovery of the SFEC might be just what they’ve been looking for. “Because they will aim at specific proteins like SFEC and target a unique subdomain on the protein’s surface, future male contraceptive drugs will be known as intelligent spermicides,” Herr explains. “At UVA, we’ve coined a great name for this new drug class: ‘spermistatic.’”