The sperm binding receptor identified and named Juno
A group of immunologists from the UK (led by Gavin Wright) have identified the receptor on the egg responsible for sperm binding. The sperm protein important for the sperm-egg interaction was identified in 2005, and is called Izumo after the Japanese marriage shrine. It turns out the egg receptor was cloned during the sequencing of the human genome and was named FolR4 for folate receptor 4. Unlike FolR1-3, FolR4 does not bind folate. Now we know that FolR4 binds Izumo, and that this interaction is important for fertilization. Additionally, following fertilization, the authors provide some evidence that the remaining FolR4 receptors are cleaved from the eggs membrane, serving as an additional polyspermy block. Because of the role of FolR4 in fertilization, the authors renamed this receptor Juno, after the Roman goddess of marriage.