Signaling in Sperm: More Different than Similar

For a given sensory cell type, signaling motifs are rather uniform across phyla. By contrast, sperm from different species use diverse repertoires of sperm-specific signaling molecules and even closely related protein isoforms feature different properties and serve different functions. This surprising diversity has consequences for strategies in fertilization research and it will take some time to get the big picture. We discuss the function of receptors, ion channels, and exchangers embedded in cellular pathways from different sperm species.