Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1999 Jul 30;274(31):21963-72.
doi: 10.1074/jbc.274.31.21963.

26 S proteasome-mediated production of an authentic major histocompatibility class I-restricted epitope from an intact protein substrate

S Ben-Shahar  1 , A Komlosh, E Nadav, I Shaked, T Ziv, A Admon, G N DeMartino, Y Reiss
Affiliations
Free article

26 S proteasome-mediated production of an authentic major histocompatibility class I-restricted epitope from an intact protein substrate

S Ben-Shahar et al. J Biol Chem. .
Free article

Abstract

Peptides displayed on the cell surface by major histocompatibility class I molecules (MHC class I) are generated by proteolytic processing of protein-antigens in the cytoplasm. Initially, antigens are degraded by the 26 S proteasome, most probably following ubiquitination. However, it is unclear whether this proteolysis results in the generation of MHC class I ligands or if further processing is required. To investigate the role of the 26 S proteasome in antigen presentation, we analyzed the processing of an intact antigen by purified 26 S proteasome. A recombinant ornithine decarboxylase was produced harboring the H-2K(b)-restricted peptide epitope, derived from ovalbumin SIINFEKL (termed ODC-ova). Utilizing recombinant antizyme to target the antigen to the 26 S proteasome, we found that proteolysis of ODC-ova by the 26 S proteasome resulted in the generation of the K(b)-ligand. Mass spectrometry analysis indicated that in addition to SIINFEKL, the N-terminally extended ligand, HSIINFEKL, was also generated. Production of SIINFEKL was linear with time and directly proportional to the rate of ODC-ova degradation. The overall yield of SIINFEKL was approximately 5% of the amount of ODC-ova degraded. The addition of PA28, the 20 S, or the 20 S-PA28 complex to the 26 S proteasome did not significantly affect the yield of the antigenic peptide. These findings demonstrate that the 26 S proteasome can efficiently digest an intact physiological substrate and generate an authentic MHC class I-restricted epitope.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

MeSH terms

LinkOut - more resources