The unexpected effect of the protease CPAF from <i>Chlamydia trachomatis</i>is to increase the global synthesis of the host proteins

Abstract MHC-I molecules are involved in the predisposition to several immune diseases. Reactive arthritis (ReA) is strongly linked with Chlamydia trachomatisinfection and HLA-B*27. However, how can contribute pathology not well understood. Chlamydiais an intracellular pathogen one of its main pathogenic factors CPAF. This enzyme secreted cytosol host during infection there no data regarding global effect on protein degradation could affect ligands presented by molecules. T-REx-293 cells stably transfected CPAF were induced doxycycline effects known substrates assayed Western blot. Moreover, unknown proteome evaluated label-free quantitation (LFQ) using a Q-Exactive plus mass spectrometer. Additionally, complexes purified immunoprecipitation eluted peptides analyzed MS. highly active degrading such as Vimentin RFX5, but also showed unexpected profound cellular increasing expression many proteins wide range functions, mostly related transcription translation pathways. More than 3000 MHC-I-restricted identified showing that peptidome altered when induced, diversity altering physicochemical properties peptides. As conclusion, deeply alters contributing alter peptide supply antigen processing pathway which composition MHC-I-associated immunopeptidome. These suggest generation “new ligands” be new mechanism C. trachomatisin ReA. Supported grants Fondecyt 11170969 Fondequip EQM190142 from ANID, Chile.