TY - JOUR TI - TAPBPR bridges UDP-glucose:glycoprotein glucosyltransferase 1 onto MHC class I to provide quality control in the antigen presentation pathway AU - Neerincx, Andreas AU - Hermann, Clemens AU - Antrobus, Robin AU - van Hateren, Andy AU - Cao, Huan AU - Trautwein, Nico AU - Stevanović, Stefan AU - Elliott, Tim AU - Deane, Janet E AU - Boyle, Louise H A2 - Margulies, David H VL - 6 PY - 2017 DA - 2017/04/20 SP - e23049 C1 - eLife 2017;6:e23049 DO - 10.7554/eLife.23049 UR - https://doi.org/10.7554/eLife.23049 AB - Recently, we revealed that TAPBPR is a peptide exchange catalyst that is important for optimal peptide selection by MHC class I molecules. Here, we asked whether any other co-factors associate with TAPBPR, which would explain its effect on peptide selection. We identify an interaction between TAPBPR and UDP-glucose:glycoprotein glucosyltransferase 1 (UGT1), a folding sensor in the calnexin/calreticulin quality control cycle that is known to regenerate the Glc1Man9GlcNAc2 moiety on glycoproteins. Our results suggest the formation of a multimeric complex, dependent on a conserved cysteine at position 94 in TAPBPR, in which TAPBPR promotes the association of UGT1 with peptide-receptive MHC class I molecules. We reveal that the interaction between TAPBPR and UGT1 facilities the reglucosylation of the glycan on MHC class I molecules, promoting their recognition by calreticulin. Our results suggest that in addition to being a peptide editor, TAPBPR improves peptide optimisation by promoting peptide-receptive MHC class I molecules to associate with the peptide-loading complex. KW - TAPBPR KW - TAPBPL KW - antigen processing & presentation KW - MHC KW - HLA JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -