Functional disparity between human PAWP and PLCζ in the generation of Ca2+oscillations for oocyte activation
Michail Nomikos, Jessica R. Sanders, Junaid Kashir, Randa Sanusi, Luke Buntwal, Daniel Love, Peter Ashley, David Sanders, Paul Knaggs, Adnan Bunkheila, Karl Swann, and F. Anthony Lai
in Mol. Hum. Reprod. (2015) 21 (9): 702-710 doi:10.1093/molehr/gav034
What in the sperm stimulates the egg to get excited and resume development? A key experiment in this arena is the injection (or production) of sperm factor(s) and subsequent examination of calcium oscillations in the egg. So what is the sperm factor? Until recently the answer was a resounding PLCζ. However another candidate PAWP (a post-acrosomal sheath WW domain-binding protein ) has been proposed as an alternative. The debate is a very topical and sometimes heated. In this paper, Lai and colleagues perform a series of experiments producing, for example, recombinant proteins from both candidates. Significant disparities between previous results using PAWP were observed leading the authors to conclude that PAWP was neither sufficient nor necessary for stimulation of calcium oscillations. The debate is likely to continue and it will be interesting to see results of the knock-out mouse.