Calcium Signaling in Mammalian Eggs at Fertilization

Title:Calcium Signaling in Mammalian Eggs at Fertilization

Volume: 16 Issue: 24

Author(s): Hideki Shirakawa, Takashi Kikuchi and Masahiko Ito

Affiliation:

Keywords: Calcium influx, Calcium oscillations, Calcium release, Calcium wave, Egg activation, Fertilization, Fluorescence imaging, Infertility, Inositol 1, 4, 5-trisphosphate, Phospholipase Cζ.

Abstract: The innovation and development of live-cell fluorescence imaging methods have revealed the dynamic aspects of intracellular Ca²⁺ in a wide variety of cells. The fertilized egg, the very first cell to be a new individual, has long been under extensive investigations utilizing Ca²⁺ imaging since its early days, and spatiotemporal Ca²⁺ dynamics and underlying mechanisms of Ca²⁺ mobilization, as well as physiological roles of Ca²⁺ at fertilization, have become more or less evident in various animal species. In this article, we illustrate characteristic patterns of Ca²⁺ dynamics in mammalian gametes and molecular basis for Ca²⁺ release from intracellular stores leading to the elevation in cytoplasmic Ca²⁺ concentration, and describe the identity and properties of sperm-borne egg-activating factor in relation to the induction of Ca²⁺ waves and Ca²⁺ oscillations, referring to its potential use in artificial egg activation as infertility treatment. In addition, a possible Ca²⁺ influx-driven mechanism for slow and long-lasting Ca²⁺ oscillations characteristic of mammalian eggs is proposed, based on the recent experimental findings and mathematical modeling. Cumulative knowledge about the roles of Ca²⁺ in the egg activation leading to early embryogenesis is summarized, to emphasize the diversity of functions that Ca²⁺ can perform in a single type of cell.

Cite this article as:

Shirakawa Hideki, Kikuchi Takashi and Ito Masahiko, Calcium Signaling in Mammalian Eggs at Fertilization, Current Topics in Medicinal Chemistry 2016; 16 (24) . https://dx.doi.org/10.2174/1568026616666160413135406