SGK phosphorylates Cdc25 and Myt1 to trigger cyclin B-Cdk1 activation at the meiotic G2/M transition.
J Cell Biol
; 218(11): 3597-3611, 2019 11 04.
Article
en En
| MEDLINE
| ID: mdl-31537708
ABSTRACT
The kinase cyclin B-Cdk1 complex is a master regulator of M-phase in both mitosis and meiosis. At the G2/M transition, cyclin B-Cdk1 activation is initiated by a trigger that reverses the balance of activities between Cdc25 and Wee1/Myt1 and is further accelerated by autoregulatory loops. In somatic cell mitosis, this trigger was recently proposed to be the cyclin A-Cdk1/Plk1 axis. However, in the oocyte meiotic G2/M transition, in which hormonal stimuli induce cyclin B-Cdk1 activation, cyclin A-Cdk1 is nonessential and hence the trigger remains elusive. Here, we show that SGK directly phosphorylates Cdc25 and Myt1 to trigger cyclin B-Cdk1 activation in starfish oocytes. Upon hormonal stimulation of the meiotic G2/M transition, SGK is activated by cooperation between the Gßγ-PI3K pathway and an unidentified pathway downstream of Gßγ, called the atypical Gßγ pathway. These findings identify the trigger in oocyte meiosis and provide insights into the role and activation of SGK.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fase G2
/
Proteína Quinasa CDC2
/
Proteínas Serina-Treonina Quinasas
/
Proteínas Inmediatas-Precoces
/
Ciclina B
/
Fosfatasas cdc25
/
Asterina
/
Meiosis
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Cell Biol
Año:
2019
Tipo del documento:
Article
País de afiliación:
Japón