The chaperone activity of protein disulfide isomerase is affected by cyclophilin B and cyclosporin A in vitro.
J Biochem
; 132(3): 401-7, 2002 Sep.
Article
em En
| MEDLINE
| ID: mdl-12204109
ABSTRACT
To elucidate the function of protein disulfide isomerase (PDI), we screened for PDI-binding proteins in a bovine liver extract using affinity column chromatography. One of the binding proteins was identified by SDS-PAGE and N-terminal amino acid sequence analysis to be cyclophilin B (Cyp B). Use of the BIACORE system revealed that purified bovine Cyp B bound specifically to bovine PDI with a K(D) value of 1.19 x 10(-5) M. Interestingly, the binding affinity between PDI and Cyp B was strengthened by preincubation of the Cyp B with cyclosporin A (CsA), yielding a K(D) value of 3.67 x 10(-6) M. Although the interaction between PDI and Cyp B affected neither the isomerase activity of PDI nor the peptidyl-prolyl cis-trans isomerase activity of Cyp B, Cyp B increased the chaperone activity of PDI. However, the complex of Cyp B and CsA completely inhibited the chaperone activity of PDI. Thus, PDI and Cyp B appear to cooperate with each other to regulate the functional expression of proteins in vivo.
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Base de dados:
MEDLINE
Assunto principal:
Ciclosporina
/
Chaperonas Moleculares
/
Isomerases de Dissulfetos de Proteínas
/
Ciclofilinas
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article