The egg membrane microdomain-associated uroplakin III-Src system becomes functional during oocyte maturation and is required for bidirectional gamete signaling at fertilization in Xenopus laevis.
Development
; 141(8): 1705-14, 2014 Apr.
Article
en En
| MEDLINE
| ID: mdl-24715460
ABSTRACT
In Xenopus laevis, sperm-egg interaction promotes partial proteolysis and/or tyrosine phosphorylation of uroplakin III (UPIII) and the tyrosine kinase Src, which both localize to the cholesterol-enriched egg membrane microdomains (MDs). Here we show that sperm promote proteolysis and/or tyrosine phosphorylation of UPIII and Src in MDs isolated from ovulated and unfertilized eggs (UF-MDs). An antibody against the extracellular domain of UPIII interferes with these events. Inhibition of fertilization by anti-UPIII antibody is rescued by co-incubation with UF-MDs. This suggests that, like MDs in intact eggs, the isolated UF-MDs are capable of interacting with sperm, an interaction that does not interfere with normal fertilization but rather augments the ability of sperm to fertilize eggs pretreated with anti-UPIII antibody. This unexpected effect of UF-MDs on sperm requires UPIII function in UF-MDs and protein kinase activity in sperm. MDs isolated from progesterone-treated mature oocytes, but not ovarian immature oocytes, are similarly functional as UF-MDs. The anti-UPIII extracellular domain antibody binds more effectively to the surface of mature than immature ovarian oocytes. We propose that the structural and functional competency of the UPIII-Src signaling system in MDs is strictly regulated during oocyte maturation and subsequently in sperm-mediated egg activation and fertilization. The fertilization-related signaling properties seen in UF-MDs can be partially reconstituted in MDs of human embryonic kidney 293 cells (293-MDs) expressing UPIII, Src and uroplakin Ib. However, 293-MDs expressing a proteolysis-resistant mutant of UPIII are less functional, suggesting that the availability of UPIII to protease action is important for MD function.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Oocitos
/
Óvulo
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Xenopus laevis
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Familia-src Quinasas
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Microdominios de Membrana
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Fertilización
/
Uroplaquina III
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
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Female
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Humans
/
Male
Idioma:
En
Revista:
Development
Asunto de la revista:
BIOLOGIA
/
EMBRIOLOGIA
Año:
2014
Tipo del documento:
Article
País de afiliación:
Japón