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Egg activation: Upstream of the fertilization calcium signal
Author(s) -
Ciapa Brigitte,
Chiri Sandrine
Publication year - 2000
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/s0248-4900(00)01065-0
Subject(s) - biology , oocyte activation , zygote , calcium , microbiology and biotechnology , human fertilization , inositol , sperm , calcium signaling , inositol trisphosphate receptor , signal transduction , calcium in biology , oocyte , gamete , receptor , embryo , embryogenesis , intracellular , biochemistry , genetics , medicine
Interaction of sperm and egg at fertilization induces well‐coordinated molecular events including specific recognition between species, adhesion and fusion, that lead to the formation of a zygote, a totipotent cell that develops into a new individual. A calcium signal, common to a great number of species, from marine invertebrates to mammals, is essential to activate the metabolism of the unfertilized oocyte. However, how fertilization triggers this calcium signal and initiates development of the early embryo is far from understood. The signaling pathways activated in eggs may be similar to those described in somatic cells, since changes in intracellular free calcium and in mitosis activating protein (MAP) kinase activity occur in both systems after activation. Several hypotheses are currently proposed, implying a spermatic ligand binding to a specific receptor expressed at the egg surface, or where the fused sperm either allows the transit of external calcium into the egg or injects one (or several) activating factor(s). It is still not known which of these ideas is true. We concentrate in this review on the possible signaling pathways involving IP 3 (inositol trisphosphate), since its production is involved in most species to generate the fertilization calcium wave.