PLCζ and its role as a trigger of development in vertebrates

A major unresolved issue in developmental biology is the precise mechanism whereby the sperm activates the oocyte. With the discovery that calcium signals are the primary trigger for oocyte activation, a key remaining question became the identification of the signaling protein that mediates such calcium signals at fertilization. A major step forward came in 2002 with the discovery of a sperm‐specific mammalian phospholipase C called phospholipase C zeta (PLC ζ) , which had the expected properties of the mammalian oocyte activation factor and was subsequently identified in other vertebrate groups. Most recently, defects in PLC ζ have been shown to be linked to certain types of male infertility in humans. Despite these advances, many questions remain about the precise mechanism of action of PLC ζ and the extent of its role during oocyte activation in the vertebrate kingdom. In this review, we will look at the current state of understanding of PLC ζ 's mechanism of action and physiological role in mammals and other vertebrates, and identify areas of uncertainty that still remain to be resolved. Mol. Reprod. Dev. 78:846–853, 2011. © 2011 Wiley Periodicals, Inc.