B55alpha PP2A holoenzymes modulate the phosphorylation status of the retinoblastoma-related protein p107 and its activation.
J Biol Chem
; 285(39): 29863-73, 2010 Sep 24.
Article
em En
| MEDLINE
| ID: mdl-20663872
ABSTRACT
Pocket proteins negatively regulate transcription of E2F-dependent genes and progression through the G(0)/G(1) transition and the cell cycle restriction point in G(1). Pocket protein repressor activities are inactivated via phosphorylation at multiple Pro-directed Ser/Thr sites by the coordinated action of G(1) and G(1)/S cyclin-dependent kinases. These phosphorylations are reversed by the action of two families of Ser/Thr phosphatases PP1, which has been implicated in abrupt dephosphorylation of retinoblastoma protein (pRB) in mitosis, and PP2A, which plays a role in an equilibrium that counteracts cyclin-dependent kinase (CDK) action throughout the cell cycle. However, the identity of the trimeric PP2A holoenzyme(s) functioning in this process is unknown. Here we report the identification of a PP2A trimeric holoenzyme containing B55α, which plays a major role in restricting the phosphorylation state of p107 and inducing its activation in human cells. Our data also suggest targeted selectivity in the interaction of pocket proteins with distinct PP2A holoenzymes, which is likely necessary for simultaneous pocket protein activation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ciclo Celular
/
Proteína p107 Retinoblastoma-Like
/
Proteína Fosfatase 2
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Multimerização Proteica
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article