Calcium signaling differentiation during Xenopus oocyte maturation

Autor: Khaled Machaca, Shirley Haun, Wassim El-Jouni, Byungwoo Jang
Rok vydání: 2005
Předmět:
Xenopus
Receptors
Cytoplasmic and Nuclear
IP3 receptor
Calcium-Transporting ATPases
Inositol 1
4
5-Trisphosphate
In Vitro Techniques
Endoplasmic Reticulum
Sarcoplasmic Reticulum Calcium-Transporting ATPases
Plasma Membrane Calcium-Transporting ATPases
03 medical and health sciences
Human fertilization
Plasma membrane Ca2+ ATPase
Oocyte maturation
medicine
Animals
Inositol 1
4
5-Trisphosphate Receptors
Calcium Signaling
Cation Transport Proteins
Ca2+ signaling
Molecular Biology
030304 developmental biology
Calcium signaling
0303 health sciences
Ion Transport
biology
030302 biochemistry & molecular biology
Oocyte activation
Cell Biology
Inositol trisphosphate receptor
biology.organism_classification
Oocyte
Endocytosis
Cell biology
medicine.anatomical_structure
Fertilization
embryonic structures
Oocytes
Female
Calcium Channels
Intracellular
Developmental Biology
Zdroj: Developmental Biology. 288:514-525
ISSN: 0012-1606
DOI: 10.1016/j.ydbio.2005.10.034
Popis: Ca(2+) is the universal signal for egg activation at fertilization in all sexually reproducing species. The Ca(2+) signal at fertilization is necessary for egg activation and exhibits specialized spatial and temporal dynamics. Eggs acquire the ability to produce the fertilization-specific Ca(2+) signal during oocyte maturation. However, the mechanisms regulating Ca(2+) signaling differentiation during oocyte maturation remain largely unknown. At fertilization, Xenopus eggs produce a cytoplasmic Ca(2+) (Ca(2+)(cyt)) rise that lasts for several minutes, and is required for egg activation. Here, we show that during oocyte maturation Ca(2+) transport effectors are tightly modulated. The plasma membrane Ca(2+) ATPase (PMCA) is completely internalized during maturation, and is therefore unable to extrude Ca(2+) out of the cell. Furthermore, IP(3)-dependent Ca(2+) release is required for the sustained Ca(2+)(cyt) rise in eggs, showing that Ca(2+) that is pumped into the ER leaks back out through IP(3) receptors. This apparent futile cycle allows eggs to maintain elevated cytoplasmic Ca(2+) despite the limited available Ca(2+) in intracellular stores. Therefore, Ca(2+) signaling differentiates in a highly orchestrated fashion during Xenopus oocyte maturation endowing the egg with the capacity to produce a sustained Ca(2+)(cyt) transient at fertilization, which defines the egg's competence to activate and initiate embryonic development.
Databáze: OpenAIRE
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