Fig. 1: The biological functions of ERAP2.

Protein fragments (peptides) generated by cellular proteasomes are transported into the endoplasmic reticulum. ERAP2 is an aminopeptidase that trims N-terminal amino acid residues from peptides in the endoplasmic reticulum to prevent or facilitate binding to the major histocompatibility complex class I (MHC-I). The MHC-I peptide complexes are then presented on the surface of the cell to CD8 + T cells, allowing the immune system to identify and respond to infected or abnormal cells. The ERAP2 enzyme has also been shown to remove amino acid residues from naturally occurring signalling peptides, including the conversion of angiotensin derivatives [Angiotensin II/III into IV], indicating a potential role for ERAP2 in renin-angiotensin signalling. Additional unidentified pathways may be regulated by extracellular or secreted ERAP2 proteins.