Starting a new life: Sperm PLC-zeta mobilizes the Ca2+ signal that induces egg activation and embryo development : An essential phospholipase C with implications for male infertility
✍ Scribed by Michail Nomikos; Karl Swann; F. Anthony Lai
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 761 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0265-9247
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
We have discovered that a single sperm protein, phospholipase C‐zeta (PLCζ), can stimulate intracellular Ca^2+^ signalling in the unfertilized oocyte (‘egg’) culminating in the initiation of embryonic development. Upon fertilization by a spermatozoon, the earliest observed signalling event in the dormant egg is a large, transient increase in free Ca^2+^ concentration. The fertilized egg responds to the intracellular Ca^2+^ rise by completing meiosis. In mammalian eggs, the Ca^2+^ signal is delivered as a train of long‐lasting cytoplasmic Ca^2+^ oscillations that begin soon after gamete fusion and persist beyond the completion of meiosis. Sperm PLCζ effects Ca^2+^ release from egg intracellular stores by hydrolyzing the membrane lipid PIP~2~ and consequent stimulation of the inositol 1,4,5‐trisphosphate (InsP~3~) receptor Ca^2+^‐signalling pathway, leading to egg activation and early embryogenesis. Recent advances have refined our understanding of how PLCζ induces Ca^2+^ oscillations in the egg and also suggest its potential dysfunction as a cause of male infertility.