Loss of p53 enhances catalytic activity of IKKbeta through O-linked beta-N-acetyl glucosamine modification.
Proc Natl Acad Sci U S A
; 106(9): 3431-6, 2009 Mar 03.
Article
en En
| MEDLINE
| ID: mdl-19202066
ABSTRACT
The IkappaB kinase (IKK)-NF-kappaB pathway plays a critical role in oncogenesis. Recently, we have shown that p53 regulates glucose metabolism through the IKK-NF-kappaB pathway and that, in the absence of p53, the positive feedback loop between IKK-NF-kappaB and glycolysis has an integral role in oncogene-induced cell transformation. Here, we demonstrate that IKKbeta, a component of the IKK complex, was constitutively modified with O-linked beta-N-acetyl glucosamine (O-GlcNAc) in both p53-deficient mouse embryonic fibroblasts (MEFs) and transformed human fibroblasts. In p53-deficient cells, the O-GlcNAcylated IKKbeta and the activating phosphorylation of IKK were decreased by p65/NF-kappaB knockdown or glucose depletion. We also found that high glucose induced the O-GlcNAcylation of IKKbeta and sustained the TNFalpha-dependent IKKbeta activity. Moreover, the O-GlcNAcase inhibitor streptozotocin intensified O-GlcNAcylation and concomitant activating phosphorylation of IKKbeta. Mutational analysis revealed that O-GlcNAcylation of IKKbeta occurred at Ser 733 in the C-terminal domain, which was identified as an inactivating phosphorylation site, suggesting that IKKbeta O-GlcNAcylation regulates its catalytic activity. Taken together, we propose a novel mechanism for the enhancement of NF-kappaB activity by loss of p53, which evokes positive feedback regulation from enhanced glucose metabolism to IKK in oncogenesis.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Acetilglucosamina
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Proteína p53 Supresora de Tumor
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Quinasa I-kappa B
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Biocatálisis
Límite:
Animals
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Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2009
Tipo del documento:
Article
País de afiliación:
Japón