Department of Cell Biology
Acrosome Reaction; Animals; Calcium; Calcium Channel Blockers; Calcium Channels; Calcium Signaling; Chelating Agents; Egg Proteins; Egtazic Acid; Female; Ionomycin; Ionophores; Male; Manganese; Membrane Glycoproteins; Mice; Mice, Inbred Strains; *Receptors, Cell Surface; Sperm Capacitation; Spermatozoa; Thapsigargin; Verapamil
Cell Biology | Life Sciences | Medicine and Health Sciences
Fertilization occurs after the completion of the sperm acrosome reaction, a secretory event that is triggered during gamete adhesion. ZP3, an egg zona pellucida glycoprotein, produces a sustained increase of the internal Ca(2+) concentration in mouse sperm, leading to acrosome reactions. Here we show that the sustained Ca(2+) concentration increase is due to the persistent activation of a Ca(2+) influx mechanism during the late stages of ZP3 signal transduction. These cells also possess a Ca(2+) store depletion-activated Ca(2+) entry pathway that is open after treatment with thapsigargin. Thapsigargin and ZP3 activate the same Ca(2+) permeation mechanism, as demonstrated by fluorescence quenching experiments and by channel antagonists. These studies show that ZP3 generates a sustained Ca(2+) influx through a store depletion-operated pathway and that this drives the exocytotic acrosome reaction.
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Citation: Mol Biol Cell. 2000 May;11(5):1571-84. Link to article on publisher's website
O'Toole, Christine M. B.; Arnoult, Christophe; Darszon, Alberto; Steinhardt, Richard A.; and Florman, Harvey M., "Ca(2+) entry through store-operated channels in mouse sperm is initiated by egg ZP3 and drives the acrosome reaction" (2000). Open Access Articles. Paper 1399.