Identification of a starfish egg PLC-gamma that regulates Ca2+ release at fertilization.
Dev Biol
; 269(1): 220-36, 2004 May 01.
Article
en En
| MEDLINE
| ID: mdl-15081369
ABSTRACT
At fertilization, eggs undergo a cytoplasmic free Ca2+ rise, which is necessary for stimulating embryogenesis. In starfish eggs, studies using inhibitors designed against vertebrate proteins have shown that this Ca2+ rise requires an egg Src family kinase (SFK) that directly or indirectly activates phospholipase C-gamma (PLC-gamma) to produce IP3, which triggers Ca2+ release from the egg's endoplasmic reticulum (ER) [reviewed in Semin. Cell Dev. Biol. 12 (2001) 45]. To examine in more detail the endogenous factors in starfish eggs that are required for Ca2+ release at fertilization, an oocyte cDNA encoding PLC-gamma was isolated from the starfish Asterina miniata. This cDNA, designated AmPLC-gamma, encodes a protein with 49% identity to mammalian PLC-gamma1. A 58-kDa Src family kinase interacted with recombinant AmPLC-gamma Src homology 2 (SH2) domains in a specific, fertilization-responsive manner. Immunoprecipitations of sea urchin egg PLC-gamma using an affinity-purified antibody directed against AmPLC-gamma revealed fertilization-dependent phosphorylation of PLC-gamma. Injecting starfish eggs with the tandem SH2 domains of AmPLC-gamma (which inhibits PLC-gamma activation) specifically inhibited Ca2+ release at fertilization. These results indicate that an endogenous starfish egg PLC-gamma interacts with an egg SFK and mediates Ca2+ release at fertilization via a PLC-gamma SH2 domain-mediated mechanism.
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Bases de datos:
MEDLINE
Asunto principal:
Óvulo
/
Fosfolipasas de Tipo C
/
Estrellas de Mar
/
Calcio
/
Fertilización
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Dev Biol
Año:
2004
Tipo del documento:
Article
País de afiliación:
Estados Unidos