Calcium Influx and Male Fertility in the Context of the Sperm Proteome: An Update
Figure 5
Schematic representation showing the Ca2+ influx mechanism in mammalian eggs stimulated by mature spermatozoa. Spermatozoa donate the phospholipase C isoform zeta (PLCζ) protein within a few minutes of sperm-egg fusion (represented by green color circle). Inositol 1,4,5-trisphosphate (InsP3) is produced due to the hydrolysis of PLCζ, which subsequently triggers the nsP3 receptor-mediated Ca2+ release (indicated by red color circle) from the endoplasmic reticulum of the oocyte. Simultaneously, the increased cytoplasmic Ca2+ leads to further PLCζ stimulation, leading to the positive feedback loop of Ca2+ and InsP3 rise. The hypothesis has been modified from Swann [96] and Swann et al. [97].
