The successful union of egg and sperm in fertilisation depends on a sperm cell’s ability to get through an egg’s thick protective coating and latch itself to its membrane. A study published in the journal Andrology yesterday gives us our first look at the protein responsible for the tie-down.
Sperm-lysozyme-like protein 1 (SLLP1, above) is found inside a part of the sperm’s head called the acrosome, a region that was already known to host enzymes that help a sperm drill through an egg’s gelatinous coating.
University of Virginia researchers from the labs of John Herr and Wladek Minor have determined that SLLP1 looks something like the prong of a mutant USB cord: a group of six smaller proteins wrapped in a helix around a central space. The filaments plug into a protein called ovastacin that is only found near the surface of the egg. Ovastacin also plays a role in preventing multiple sperm from entering the egg, suggesting that these two proteins play a key role in sparking the process of fertilisation.
Image by Heping Zheng, Ph.D., University of Virginia School of Medicine
This post originally appeared on Throb, Gizmodo's blog for all things sex