T-cell receptor ligation causes Wiskott-Aldrich syndrome protein degradation and F-actin assembly downregulation.
J Allergy Clin Immunol
; 132(3): 648-655.e1, 2013 Sep.
Article
em En
| MEDLINE
| ID: mdl-23684068
BACKGROUND: Wiskott-Aldrich syndrome protein (WASP) links T-cell receptor (TCR) signaling to the actin cytoskeleton. WASP is normally protected from degradation by the Ca(++)-dependent protease calpain and by the proteasome because of its interaction with the WASP-interacting protein. OBJECTIVE: We investigated whether WASP is degraded after TCR ligation and whether its degradation downregulates F-actin assembly caused by TCR ligation. METHODS: Primary T cells, Jurkat T cells, and transfected 293T cells were used in immunoprecipitation experiments. Intracellular F-actin content was measured in splenic T cells from wild-type, WASP-deficient, and c-Casitas B-lineage lymphoma (Cbl)-b-deficient mice by using flow cytometry. Calpeptin and MG-132 were used to inhibit calpain and the proteasome, respectively. RESULTS: A fraction of WASP in T cells was degraded by calpain and by the ubiquitin-proteasome pathway after TCR ligation. The Cbl-b and c-Cbl E3 ubiquitin ligases associated with WASP after TCR signaling and caused its ubiquitination. Inhibition of calpain and lack of Cbl-b resulted in a significantly more sustained increase in F-actin content after TCR ligation in wild-type T cells but not in WASP-deficient T cells. CONCLUSION: TCR ligation causes WASP to be degraded by calpain and to be ubiquitinated by Cbl family E3 ligases, which targets it for destruction by the proteasome. WASP degradation might provide a mechanism for regulating WASP-dependent TCR-driven assembly of F-actin.
Palavras-chave
Actin-related protein; Arp; Casitas B-lineage lymphoma; Cbl; Cbl family proteins; EVH1; Ena-VASP homology domain 1; F-actin; IS; Immune synapse; T-cell receptor; TCR; WAS; WASP; WASP-interacting protein; WIP; WT; Wild-type; Wiskott-Aldrich syndrome; Wiskott-Aldrich syndrome protein; ZAP-70; calpain; proteasome; ubiquitination; ζ Chainassociated protein kinase of 70 kDa
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Calpaína
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Receptores de Antígenos de Linfócitos T
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Actinas
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Proteínas Adaptadoras de Transdução de Sinal
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Proteína da Síndrome de Wiskott-Aldrich
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Proteínas Proto-Oncogênicas c-cbl
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article