SLC9C1 and male infertility: Knockout (KO) studies have shown that SLC9C1 deficiency causes immotile spermatozoa and male infertility in mice, which can be rescued by cell-permeable cAMP analogs or photoactivated adenylyl cyclase, underscoring the interplay between SLC9C1 and cAMP production via sAC (14, 18).