The role of Ca2+ flux in the Acrosome Reaction
Depletion of sperm's acrosomal Ca2+ store is an important step in the acrosome reaction, which can be stimulated with thapsigargin (an intracellular Ca2+ store releaser). Thapsigargin blocks Ca2+-ATPase from pumping Ca2+ into the acrosome. The acrosome naturally expels Ca2+ into the cytosol, thus depleting the internal calcium store and opening plasma membrane Ca2+ channels. To understand the role of iPLA2, sperm from control and iPLA2 null were treated with thapsigargin and the number of acrosome reacted and motile sperm were counted. We found that both the Knockout (KO) and the Wild-type (WT) mice acrosome reacted in response to thapsigargin. In addition, sperm were treated with an inhibitor of iPLA2, bromoenol lactose (BEL). BEL partially blocks the thapsigargin-induced acrosome reaction. These data suggest that BEL has non-specific effects on the acrosome reaction and that iPLA2 functions upstream up store-operated calcium release.
School:
University of Puerto Rico at Bayamón
Department:
Human Biology
Research Advisor:
David MillerDavid Miller
Department of Research Advisor:
Reproductive Biology
Year of Publication:
2005