ERAP1 and ERAP2 are enzymes that trim peptides loaded into the classical and non-classical MCHI molecules. View our interactive image below to learn more. Hover over each of the interactive dots to learn more about the antigen presentation pathway.

Cellular proteins

  • Multiple sources of protein that feed the antigen presentation pathway.


  • The majority of peptides that feed the antigen presentation pathway are degraded by the proteasome.


  • Peptides generated by the proteasome are transported into the ER.


  • Peptides from the cytosol are transported into the ER via the TAP transporter complex.


  • ER resident aminopeptidases which trim or over-trim antigens and neoantigens prior to loading onto MHC Class I. ERAP1 and ERAP2 have different peptide specificities.

MHC Class I and CD8 T cells

  • At the cell surface the MHC Class I complex presents antigens / neoantigens to CD8 T cells where they are recognised as ‘self’ or 'non-self’.

MHC Class I

  • Peptides loaded onto the MHC Class I complex through the action of the Peptide Loading Complex (PLC) and ERAP1/2 activity are transported to the cell surface.