How SNARE proteins drive fertilization

Researchers describe, for the first time, the full molecular cascade that comprises acrosomal exocytosis, an essential step in fertilization, in this week's PLoS Biology.

"Exocytosis has been analyzed before, but the different steps were reconstructed from experiments done in different systems, including yeast and neurons," coauthor Luis Mayorga of the University of Cuyo, in Argentina, told The Scientist. "Now we have a complete picture of the process of membrane fusion occurring in one single system, from beginning to end. We expect our results to provide tools to better understand membrane fusion and control the process of fertilization."

Acrosomal exocytosis involves the fusion of acrosomal and sperm membranes, and the synchronized opening of hundreds of fusion pores between those membranes, explained Mayorga. As a result, enzymes contained in the acrosomal vesicle exit the cell, enabling the spermatozoon to penetrate the egg.

In the paper, a team led by Mayorga and Claudia ...