c-Mos proteolysis is independent of the CA(2+) rise induced by 6-DMAP in Xenopus oocytes.
Exp Cell Res
; 266(1): 187-92, 2001 May 15.
Article
em En
| MEDLINE
| ID: mdl-11339837
ABSTRACT
In Xenopus oocytes, metaphase II arrest is due to a cytostatic factor (CSF) that involves c-Mos, maintaining a high MPF (cdk1/cyclin B) activity in the cell. At fertilization, a rise in intracellular calcium triggers the proteolysis of both cyclin B and c-Mos. The kinase inhibitor 6-dimethylaminopurine (6-DMAP) is also able to release matured Xenopus oocytes from metaphase II block. This is characterized by c-Mos proteolysis without degradation of cyclin B. We hypothesized that 6-DMAP induced an increase in intracellular calcium. Using the calcium-sensitive fluorescent dye Fura-2, we observed a systematic increase in intracellular calcium following 6-DMAP application. In matured oocytes previously microinjected with the calcium chelator BAPTA, no calcium changes occurred after 6-DMAP addition; however, c-Mos was still proteolysed. In oocytes at the GVBD stage, c-Mos proteolysis occurred in response to 6-DMAP but not to calcium ionophore treatment. We suggest that c-Mos proteolysis is rather controlled by a phosphorylation-dependent process.
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Base de dados:
MEDLINE
Assunto principal:
Oócitos
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Peptídeo Hidrolases
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Xenopus laevis
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Adenina
/
Cálcio
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Proteínas Proto-Oncogênicas c-mos
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Inibidores Enzimáticos
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article