Molecular Reproduction & Development Volume 78, Issue 12 cover image

Signal transduction across plasma membrane is prerequisite for activation of sperm motility and sperm chemotaxis at fertilization. An oscillatory increase in intracellular calcium occurs upon activation of tunicate sperm (shown in false color in the foreground, clockwise displaying later time points; starting at 11:00). Zhu and Inaba (this issue) report that lipid rafts are essential for these calcium dynamics and for subsequent activation of adenylyl cyclase. Background image is of a single tunicate, Ciona intestinalis.