E3 Ubiquitin Ligase Cbl-b Regulates Thymic-Derived CD4+CD25+ Regulatory T Cell Development by Targeting Foxp3 for Ubiquitination.
J Immunol
; 194(4): 1639-45, 2015 Feb 15.
Article
em En
| MEDLINE
| ID: mdl-25560411
ABSTRACT
CD28 costimulation is essential for the development of thymic-derived CD4(+)CD25(+)Foxp3(+) regulatory T cells ("tTregs"). E3 ubiquitin ligase Cbl-b has been shown to regulate CD28 dependence of T cell activation. In this paper, we report that the loss of Cbl-b partially but significantly rescues the defective development of tTregs in Cd28(-/-) mice. This partial rescue is independent of IL-2. Mechanistically, Cbl-b binds to Foxp3 upon TCR stimulation and, together with Stub1, targets Foxp3 for ubiquitination and subsequently degradation in the proteasome. As Cbl-b self-ubiquitination and proteasomal degradation is impaired in Cd28(-/-) T cells, the defective development of tTregs in Cd28(-/-) mice may in part be due to increased Foxp3 ubiquitination and degradation targeted by Stub1 and Cbl-b. Treating Cd28(-/-) mice with a proteasome inhibitor completely rescues defective tTreg development in these mice. Therefore, Cbl-b, together with Stub1, ubiquitinate Foxp3, and regulate tTreg development.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ativação Linfocitária
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Linfócitos T Reguladores
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Proteínas Adaptadoras de Transdução de Sinal
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Proteínas Proto-Oncogênicas c-cbl
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Fatores de Transcrição Forkhead
Limite:
Animals
Idioma:
En
Revista:
J Immunol
Ano de publicação:
2015
Tipo de documento:
Article