Fbxw5 suppresses nuclear c-Myb activity via DDB1-Cul4-Rbx1 ligase-mediated sumoylation.
Biochem Biophys Res Commun
; 426(1): 59-64, 2012 Sep 14.
Article
em En
| MEDLINE
| ID: mdl-22910413
ABSTRACT
The c-myb proto-oncogene product (c-Myb) is degraded in response to Wnt-1 signaling. In this process, Fbxw7α, the F-box protein of the SCF complex, binds to c-Myb via its C-terminal WD40 domain, and induces the ubiquitination of c-Myb. Here, we report that Fbxw5, another F-box protein, enhances sumoylation of nuclear c-Myb. Fbxw5 enhanced c-Myb sumoylation via the DDB1-Cul4A-Rbx1 complex. Since the Fbxw5-DDB1-Cul4A-Rbx1 complex was shown to act as a ubiquitin ligase for tumor suppressor TSC2, our results suggest that this complex can function as a dual SUMO/ubiquitin ligase. Fbxw5, which is localized to both nucleus and cytosol, enhanced sumoylation of nuclear c-Myb and induced the localization of c-Myb to nuclear dot-like domains. Co-expression of Fbxw5 suppressed the trans-activation of c-myc promoter by wild-type c-Myb, but not by v-Myb, which lacks the sumoylation sites. These results suggest that multiple E3 ligases suppress c-Myb activity through sumoylation or ubiquitination, and that v-Myb is no longer subject to these negative regulations.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Transporte
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Proteínas Proto-Oncogênicas c-myb
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Ubiquitina-Proteína Ligases
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Proteínas Culina
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Proteínas F-Box
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Proteínas de Ligação a DNA
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Sumoilação
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Biochem Biophys Res Commun
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Japão