Two novel routes of transporter associated with antigen processing (TAP)-independent major histocompatibility complex class I antigen processing.
J Exp Med
; 186(7): 1087-98, 1997 Oct 06.
Article
en En
| MEDLINE
| ID: mdl-9314557
Jaw1 is an endoplasmic reticulum (ER) resident protein representative of a class of proteins post translationally inserted into membranes via a type II membrane anchor (cytosolic NH2 domain, lumenal COOH domain) in a translocon-independent manner. We found that Jaw1 can efficiently deliver a COOH-terminal antigenic peptide to class I molecules in transporter associated with antigen processing (TAP)-deficient cells or cells in which TAP is inactivated by the ICP47 protein. Peptide delivery mediated by Jaw1 to class I molecules was equal or better than that mediated by the adenovirus E3/19K glycoprotein signal sequence, and was sufficient to enable cytofluorographic detection of newly recruited thermostabile class I molecules at the surface of TAP-deficient cells. Deletion of the transmembrane region retargeted Jaw1 from the ER to the cytosol, and severely, although incompletely, abrogated its TAP-independent peptide carrier activity. Use of different protease inhibitors revealed the involvement of a nonproteasomal protease in the TAP-independent activity of cytosolic Jaw1. These findings demonstrate two novel TAP-independent routes of antigen processing; one based on highly efficient peptide liberation from the COOH terminus of membrane proteins in the ER, the other on delivery of a cytosolic protein to the ER by an unknown route.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Antígenos de Histocompatibilidad Clase I
/
Proteínas Portadoras
/
Presentación de Antígeno
/
Proteínas de la Membrana
Tipo de estudio:
Risk_factors_studies
Límite:
Humans
Idioma:
En
Revista:
J Exp Med
Año:
1997
Tipo del documento:
Article
País de afiliación:
Estados Unidos