Behaviour of CRISP1 protein during capacitation and its role in gamete interaction

Abstract

Fertilization is a complex process that requires the successful completion of a series of orchestrated steps. In most invertebrates and non-mammalian vertebrates, spermatozoa that leave the testes already have the ability to fertilize the egg. In mammals, however, testicular sperm are not yet capable of fertilizing an egg, requiring to undergo several physiological changes during their transit through the male and female reproductive tracts, known as sperm maturation and capacitation, respectively, in order to gain their fertilizing ability. Once in the proximity of the egg, sperm must pass through the cumulus cells that surround the egg, bind to and penetrate the zona pellucida (ZP) and, finally, fuse with the egg plasma membrane. Most of these events involving cell-to-matrix and cell-to-cell interactions are mediated by specific molecules present in both gametes. One of these proteins is rat epididymal protein CRISP1 (formerly known as DE)which was the first identified member of the highly conserved Cysteine-RIch Secretory Protein (CRISP) family, characterized by the presence of sixteen conserved cysteine residues, ten of which are clustered in the C-terminal domain of the molecule. The present manuscript will focus on the results obtained in our laboratory on both the behavior of CRISP1 during capacitation and its role in gamete interaction.