Cdk-inhibitory activity and stability of p27Kip1 are directly regulated by oncogenic tyrosine kinases.
Cell
; 128(2): 269-80, 2007 Jan 26.
Article
en En
| MEDLINE
| ID: mdl-17254966
ABSTRACT
p27Kip1 controls cell proliferation by binding to and regulating the activity of cyclin-dependent kinases (Cdks). Here we show that Cdk inhibition and p27 stability are regulated through direct phosphorylation by tyrosine kinases. A conserved tyrosine residue (Y88) in the Cdk-binding domain of p27 can be phosphorylated by the Src-family kinase Lyn and the oncogene product BCR-ABL. Y88 phosphorylation does not prevent p27 binding to cyclin A/Cdk2. Instead, it causes phosphorylated Y88 and the entire inhibitory 3(10)-helix of p27 to be ejected from the Cdk2 active site, thus restoring partial Cdk activity. Importantly, this allows Y88-phosphorylated p27 to be efficiently phosphorylated on threonine 187 by Cdk2 which in turn promotes its SCF-Skp2-dependent degradation. This direct link between transforming tyrosine kinases and p27 may provide an explanation for Cdk kinase activities observed in p27 complexes and for premature p27 elimination in cells that have been transformed by activated tyrosine kinases.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Oncogenes
/
Regulación Neoplásica de la Expresión Génica
/
Transformación Celular Neoplásica
/
Quinasas Ciclina-Dependientes
/
Familia-src Quinasas
/
Inhibidor p27 de las Quinasas Dependientes de la Ciclina
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Cell
Año:
2007
Tipo del documento:
Article
País de afiliación:
Alemania