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 sig nal transduction pathways. Intracellular Ca2+ waves are formed by rege nerative stimulation of Ca2+ release from intracellular stores by Ca2 itself. Mechanisms that rely on either inositol trisphosphate or ryan odine receptor channels have been proposed to account for Ca2+ waves i n 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 diver sity in the generation of Ca2+ waves.