Soluble adenylyl cyclase in nonmammalian sperm is directly controlled by pH, not by HCO3− or Ca2+

Proceedings of the National Academy of Sciences, Volume 123, Issue 5, February 2026. <br/>SignificanceCyclic AMP (cAMP) is a cellular messenger vital for key sperm functions, including motility and fertilization capacity. The enzyme soluble adenylyl cyclase (sAC) synthesizes cAMP. While it was thought that bicarbonate regulation of sAC was …