A research team led by scientists from Oxford University (including the Structural Genomics Consortium, the Botnar Research Centre, the Weatherall Institute of Molecular Medicine, the Wellcome Building for Molecular Physiology, and the australian Diamantina Institute in Brisbane), have successfully deciphered the molecular mechanism how an ER protease (ERAP1) functions in a key step in cellular immunity- the processing of peptide antigens that are presented to Major Histocompatibilty Complex 1 (MHC1) molecules.