title: Ca2+ signaling during mammalian fertilization: requirements, players, and adaptations.
abstract: Changes in the intracellular concentration of calcium ([Ca(2+)](i)) represent a vital signaling mechanism enabling communication among cells and between cells and the environment. The initiation of embryo development depends on a [Ca(2+)](i) increase(s) in the egg, which is generally induced during fertilization. The [Ca(2+)](i) increase signals egg activation, which is the first stage in embryo development, and that consist of biochemical and structural changes that transform eggs into zygotes. The spatiotemporal patterns of [Ca(2+)](i) at fertilization show variability, most likely reflecting adaptations to fertilizing conditions and to the duration of embryonic cell cycles. In mammals, the focus of this review, the fertilization [Ca(2+)](i) signal displays unique properties in that it is initiated after gamete fusion by release of a sperm-derived factor and by periodic and extended [Ca(2+)](i) responses. Here, we will discuss the events of egg activation regulated by increases in [Ca(2+)](i), the possible downstream targets that effect these egg activation events, and the property and identity of molecules both in sperm and eggs that underpin the initiation and persistence of the [Ca(2+)](i) responses in these species.
authors: Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors: Takuya
authors: T
authors: Wakai
authors: Veerle
authors: V
authors: Vanderheyden
authors: Rafael A
authors: RA
authors: Fissore
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology*; D005306:Fertilization / Q000502:physiology*; D006801:Humans; D008297:Male; D008322:Mammals / Q000502:physiology*; D010063:Ovum / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology