Abstract

Salmonid sperm motility is regulated by different factors, such as ion concentration, osmotic pressure, pH, and temperature. The Ca2+ cation-dependent regulation and Ca2+-binding proteins are key regulatory mechanisms in the sperm activation process. In this study, the function of transient receptor potential ankyrin 1, transient receptor potential cation channel subfamily V member 4, and Na+/Ca2+ exchanger 1 on the sperm motility of Salmo salar were studied in vitro and in silico. Sperm inhibition assay results showed that the inhibition of the Na+/Ca2+ exchanger produced a significant decrease in total and progressive motility (p 0.0001). The molecular docking-based analysis showed that inhibitor KB-R7943 binds strongly (-6.0 kcal/mol) in the Ca2+binding region in this exchanger. Additionally, it was demonstrated that, in contrast to Na+/Ca2+ exchange, neither transient receptor potential ankyrin 1 nor transient receptor potential cation channel subfamily V member 4 was directly associated with sperm motility. This research provides new and useful insights into the role of Ca2+-binding proteins present in the plasma membrane that regulate the sperm motility of Salmo salar.