Centre for Biological Sciences - External Seminar Series
Professor Karl Swann, University of Cardiff
Activation of the mammalian egg at fertilization: PLCζ and Ca 2+ oscillations
Time: 17:00
Place: Building 85, Room 2207
Synopsis
At fertilization in all mammals the sperm causes egg activation by triggering a series of intracellular Ca 2+ oscillations. We have shown that these Ca 2+ oscillations can be triggered by a sperm specific protein called phospholipase C zeta (PLCzeta). It is proposed that PLCzeta enters the egg after gamete fusion and causes production of Inositol 1,4,5 trisphosphate (InsP3) that leads to cycles of intracellular Ca2+ release. PLCzeta is special amongst PLCs because it causes Ca 2+ oscillations in eggs at very low concentrations. PLCzeta is certainly unusual in having a very high sensitivity to Ca 2+ , and in that it appears to bind to PIP2 present on intracellular vesicles rather than the plasma membrane. The role of PLCzeta may also explain some cases of male factor infertility. The use of recombinant PLCzeta may also provide a solution for some cases of failed fertilization after sperm injection (ISCI).
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