The Wnt-NLK signaling pathway inhibits A-Myb activity by inhibiting the association with coactivator CBP and methylating histone H3.
Mol Biol Cell
; 16(10): 4705-13, 2005 Oct.
Article
em En
| MEDLINE
| ID: mdl-16055500
ABSTRACT
The c-myb proto-oncogene product (c-Myb) regulates proliferation and differentiation of hematopoietic cells. Recently we have shown that c-Myb is degraded in response to Wnt-1 stimulation via a pathway involving TAK1 (TGF-beta-activated kinase), HIPK2 (homeodomain-interacting protein kinase 2), and NLK (Nemo-like kinase). NLK and HIPK2 bind directly to c-Myb and phosphorylate c-Myb at multiple sites, inducing its ubiquitination and proteasome-dependent degradation. The mammalian myb gene family contains two members in addition to c-myb, A-myb, and B-myb. Here, we report that the Wnt-NLK pathway also inhibits A-Myb activity, but by a different mechanism. As in the case of c-Myb, both NLK and HIPK2 bound directly to A-Myb and inhibited its activity. NLK phosphorylated A-Myb, but did not induce A-Myb degradation. Overexpression of NLK inhibited the association between A-Myb and the coactivator CBP, thus, blocking A-Myb-induced trans-activation. The kinase activity of NLK is required for the efficient inhibition of the association between A-Myb and CBP, although the kinase-negative form of NLK also partly inhibits the interaction between A-Myb and CBP. Furthermore, NLK induced the methylation of histone H3 at lysine-9 at A-Myb-bound promoter regions. Thus, the Wnt-NLK pathway inhibits the activity of each Myb family member by different mechanisms.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Histonas
/
Transativadores
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Proteínas Proto-Oncogênicas
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Proteínas Quinases Ativadas por Mitógeno
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Proteína de Ligação a CREB
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Proteínas Wnt
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Mol Biol Cell
Ano de publicação:
2005
Tipo de documento:
Article