Interaction of TAPBPR, a tapasin homolog, with MHC-I molecules promotes peptide editing.
Proc Natl Acad Sci U S A
; 113(8): E1006-15, 2016 Feb 23.
Article
em En
| MEDLINE
| ID: mdl-26869717
ABSTRACT
Peptide loading of major histocompatibility complex class I (MHC-I) molecules is central to antigen presentation, self-tolerance, and CD8(+) T-cell activation. TAP binding protein, related (TAPBPR), a widely expressed tapasin homolog, is not part of the classical MHC-I peptide-loading complex (PLC). Using recombinant MHC-I molecules, we show that TAPBPR binds HLA-A*0201 and several other MHC-I molecules that are either peptide-free or loaded with low-affinity peptides. Fluorescence polarization experiments establish that TAPBPR augments peptide binding by MHC-I. The TAPBPR/MHC-I interaction is reversed by specific peptides, related to their affinity. Mutational and small-angle X-ray scattering (SAXS) studies confirm the structural similarities of TAPBPR with tapasin. These results support a role of TAPBPR in stabilizing peptide-receptive conformation(s) of MHC-I, permitting peptide editing.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Imunoglobulinas
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Antígeno HLA-A2
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Apresentação de Antígeno
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Proteínas de Membrana
Limite:
Animals
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Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2016
Tipo de documento:
Article