The outermost N-terminal region of tapasin facilitates folding of major histocompatibility complex class I
Författare
Summary, in English
Tapasin (Tpn) is an ER chaperone that is uniquely dedicated to MHC-I biosynthesis. It binds MHC-I molecules, integrates them into peptide-loading complexes, and exerts quality control of the bound peptides; only when an "optimal peptide" is bound will the MHC-I be released and exported to the cell surface for presentation to T cells. The exact mechanisms of Tpn quality control and the criteria for being an optimal peptide are still unknown. Here, we have generated a recombinant fragment of human Tpn, Tpn(1-87) (representing the 87 N-terminal and ER-luminal amino acids of the mature Tpn protein). Using a biochemical peptide-MHC-I-binding assay, recombinant Tpn(1-87) was found to specifically facilitate peptide-dependent folding of HLA-A*0201. Furthermore, we used Tpn(1-87) to generate a monoclonal antibody, alpha Tpn(1-87/80), specific for natural human Tpn and capable of cellular staining of ER localized Tpn. Using overlapping peptides, the epitope of alpha Tpn(1-87)/80 was located to Tpn(40-44), which maps to a surface-exposed loop on the Tpn structure. Together, these results demonstrate that the N-terminal region of Tpn can be recombinantly expressed and adopt a structure, which at least partially resembles that of WT Tpn, and that this region of Tpn features chaperone activity facilitating peptide binding of MHC-I.
Avdelning/ar
- Neurokirurgi
- Immunology
Publiceringsår
2009
Språk
Engelska
Sidor
2682-2694
Publikation/Tidskrift/Serie
European Journal of Immunology
Volym
39
Issue
10
Dokumenttyp
Artikel i tidskrift
Förlag
John Wiley & Sons Inc.
Ämne
- Immunology in the medical area
Nyckelord
- Antibodies
- Antigen processing
- MHC-I
Status
Published
Forskningsgrupp
- Immunology
ISBN/ISSN/Övrigt
- ISSN: 1521-4141