REDUNDANT MECHANISMS OF CALCIUM-INDUCED CALCIUM-RELEASE UNDERLYING CALCIUM WAVES DURING FERTILIZATION OF SEA-URCHIN EGGS

Propagating Ca2+ waves are a characteristic feature of Ca2+-linked signal transduction pathways. Intracellular Ca2+ waves are formed by regenerative stimulation of Ca2+ release from intracellular stores by Ca2+ itself. Mechanisms that rely on either inositol trisphosphate or ryanodine receptor channels have been proposed to account for Ca2+ waves in various cell types. Both channel types contributed to the Ca2+ wave during fertilization of sea urchin eggs. Alternative mechanisms of Ca2+ release imply redundancy but may also allow for modulation and diversity in the generation of Ca2+ waves.