DOI: 10.5061/dryad.487j9
title: Data from: TAPBPR alters MHC class I peptide presentation by functioning as a peptide exchange catalyst

description: Our understanding of the antigen presentation pathway has recently been
 enhanced with the identification that the tapasin-related protein TAPBPR
 is a second MHC I-specific chaperone. We sought to determine whether, like
 tapasin, TAPBPR can also influence MHC I peptide selection by functioning
 as a peptide exchange catalyst. We show that TAPBPR can catalyse the
 dissociation of peptides from peptide-MHC I complexes, enhance the loading
 of peptide-receptive MHC I molecules, and discriminate between peptides
 based on affinity in vitro. In cells, the depletion of TAPBPR increased
 the diversity of peptides presented on MHC I molecules, suggesting that
 TAPBPR is involved in restricting peptide presentation. Our results
 suggest TAPBPR binds to MHC I in a peptide-receptive state and, like
 tapasin, works to enhance peptide optimisation. It is now clear there are
 two MHC class I specific peptide editors, tapasin and TAPBPR, intimately
 involved in controlling peptide presentation to the immune system.
description: Figure 5C - Peptides
 eluted from MHC class I molecules in Hela+IFNy and Hela-TAPBPR
 KO+IFNyPeptide-MHC class I
 complexes were isolated by affinity chromatography using W6/32 from IFN-γ
 treated HeLa and HeLa-TAPBPR KO cells. Eluted peptides were analysed using
 LC-MS/MS. Peptides were assigned as HLA-A*68:02 and HLA-B*15:03 binders
 based on their peptide motifs using the online programme
 NetMHC.Hela
 IFNy and Hela IFNy TAPBPR
 KO.xlsxFigure 5D - peptides
 eluted from HeLa and HeLa-WT-TAPBPR cellsPeptide-MHC class I
 complexes were isolated by affinity chromatography using W6/32 from HeLa
 and HeLa overexpressing WT-TAPBPR. Eluted peptides were analysed using
 LC-MS/MS. Peptides were assigned as HLA-A*68:02 and HLA-B*15:03 binders
 based on their peptide motifs using the online programme
 NetMHC.HeLa
 and HeLa WT TAPBPR.xlsxFigure 5 - Figure
 supplement 1 - Peptides eluted from HeLa-S+IFNy and
 HeLa-S-shTAPBPR+IFNyPeptide-MHC class I
 complexes were isolated by affinity chromatography using W6/32 from IFN-γ
 treated HeLa-S cells and IFN-γ treated HeLa-S cells depleted of TAPBPR
 using shRNA. Eluted peptides were analysed using LC-MS/MS. Peptides were
 assigned as HLA-A*68:02 and HLA-B*15:03 binders based on their peptide
 motifs using the online programme NetMHC.HeLa IFNy and HeLa INFy
 shTAPBPR.xlsxFigure 6B - Peptide
 eluted from HLA-A2 from WT, TAPBPR depleted, and tapasin deficient KBM-7
 cellsPeptide loaded HLA-A2
 complexes were isolated using affinity chromatography with BB7.2 from
 IFN-γ treated WT, TAPBPR stably depleted (shTAPBPR) and tapasin deficient
 (TPN-) KBM-7 cells. Eluted peptide were analysed using
 LC-MS/MS.KBM7 elution from
 BB72.xlsxFigure 6E - Peptides
 eluted from HLA-B & -C from WT, TAPBPR depleted and tapasin deficient
 KBM-7 cellsHLA-B and -C complexes
 were isolated using affinity chromatography using B1.23.2 from IFN-γ
 treated WT, TAPBPR stably depleted (shTAPBPR) and tapasin deficient (TPN-)
 KBM-7 cells. Eluted peptide were analysed using
 LC-MS/MS.KBM7 elution from
 B1232.xlsx