464
Cellular Interactions
Keywords
[Ca
2
+
]
i
(Concentration of Intracellular-free Calcium)
When the egg is fertilized, there is a large rise in [Ca
2
+
]
i
that propagates across the
entire cell, and in mammalian eggs this is followed by oscillations in the level of
intracellular-free calcium.
CaM KII (Calcium/Calmodulin-dependent Protein Kinase II)
In the egg, it is involved with the meiotic metaphase II to anaphase II/telophase II
transition.
Cytoskeleton
A complex network of protein Flaments within a cell that continuously reorganizes to
adopt different shapes and functions.
Egg Activation
A process that converts an egg into a zygote. It is naturally triggered by fertilization but
can be experimentally induced by calcium ionophore.
Signal Transduction
Relaying of an extracellular signal into a cell then amplifying the signal quickly within
the cell to create a cellular response.
MAP Kinase (Mitogen-activated Protein Kinase)
Mediates the events triggered by extracellular signals in the egg. Prohibits pronuclear
formation and appears to be responsible for the changes in the organizational state of
the microtubules (interphase to metaphase).
Molecular Scaffold
Cellular structures that localize elements of assembly pathways and provide a means
for different kinase pathways to interact in discrete regions of the cell.
PKC (Protein Kinase C)
General cytoplasmic signal inducing agent in cells. In the egg, it supports the
interphase conFguration of DNA and is involved with the second polar body formation
and cortical granule exocytosis.
¥
The developmental transition of fertilization is a major organizational and functional
change, which initiates a rapid series of changes that restructures the egg into the
zygote. A series of cytoplasmic signal transduction events mediate these changes
after the sperm penetrates the egg, resulting in a rise in [Ca
2
+
]
i
. The egg undergoes
rapid structural changes that result in the extensive remodeling of this specialized
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