PMID- 37307450 OWN - NLM STAT- MEDLINE DCOM- 20230614 LR - 20230701 IS - 1091-6490 (Electronic) IS - 0027-8424 (Print) IS - 0027-8424 (Linking) VI - 120 IP - 25 DP - 2023 Jun 20 TI - Dynamic interactome of the MHC I peptide loading complex in human dendritic cells. PG - e2219790120 LID - 10.1073/pnas.2219790120 [doi] LID - e2219790120 AB - Dendritic cells (DCs) orchestrate immune responses by presenting antigenic peptides on major histocompatibility complex (MHC) molecules to T cells. Antigen processing and presentation via MHC I rely on the peptide-loading complex (PLC), a supramolecular machinery assembled around the transporter associated with antigen processing (TAP), which is the peptide transporter in the endoplasmic reticulum (ER) membrane. We studied antigen presentation in human DCs by isolating monocytes from blood and differentiating them into immature and mature DCs. We uncovered that during DC differentiation and maturation, additional proteins are recruited to the PLC, including B-cell receptor-associated protein 31 (BAP31), vesicle-associated membrane protein-associated protein A (VAPA), and extended synaptotagmin-1 (ESYT1). We demonstrated that these ER cargo export and contact site-tethering proteins colocalize with TAP and are within 40 nm proximity of the PLC, suggesting that the antigen processing machinery is located near ER exit- and membrane contact sites. While CRISPR/Cas9-mediated deletion of TAP and tapasin significantly reduced MHC I surface expression, single-gene deletions of the identified PLC interaction partners revealed a redundant role of BAP31, VAPA, and ESYT1 in MHC I antigen processing in DCs. These data highlight the dynamics and plasticity of PLC composition in DCs that previously was not recognized by the analysis of cell lines. FAU - Barends, Martina AU - Barends M AD - Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany. FAU - Koller, Nicole AU - Koller N AD - Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany. FAU - Scholz, Christian AU - Scholz C AUID- ORCID: 0000-0002-1633-2072 AD - Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-Universitat Munchen, 80336 Munich, Germany. FAU - Duran, Veronica AU - Duran V AD - Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany. FAU - Bosnjak, Berislav AU - Bosnjak B AUID- ORCID: 0000-0003-3374-7488 AD - Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany. FAU - Becker, Jennifer AU - Becker J AD - Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany. FAU - Doring, Marius AU - Doring M AUID- ORCID: 0000-0002-5278-8376 AD - Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany. FAU - Blees, Hanna AU - Blees H AD - Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany. FAU - Forster, Reinhold AU - Forster R AD - Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany. AD - Cluster of Excellence (EXC 2155) - Resolving Infection Susceptibility, Hannover Medical School, 30625 Hannover, Germany. FAU - Kalinke, Ulrich AU - Kalinke U AUID- ORCID: 0000-0003-0503-9564 AD - Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, a Joint Venture between the Helmholtz Centre for Infection Research and the Hannover Medical School, 30625 Hannover, Germany. AD - Cluster of Excellence (EXC 2155) - Resolving Infection Susceptibility, Hannover Medical School, 30625 Hannover, Germany. FAU - Tampe, Robert AU - Tampe R AUID- ORCID: 0000-0002-0403-2160 AD - Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20230612 PL - United States TA - Proc Natl Acad Sci U S A JT - Proceedings of the National Academy of Sciences of the United States of America JID - 7505876 RN - 0 (Peptides) RN - 0 (Histocompatibility Antigens Class I) RN - 0 (ESYT1 protein, human) RN - 134193-27-4 (Synaptotagmins) SB - IM MH - Humans MH - *Peptides MH - *Major Histocompatibility Complex MH - Antigen Presentation MH - Dendritic Cells MH - Histocompatibility Antigens Class I MH - Synaptotagmins PMC - PMC10288655 OTO - NOTNLM OT - antigen presentation OT - antigen processing OT - membrane organization OT - membrane proteins OT - primary cells COIS- The authors declare no competing interest. EDAT- 2023/06/12 19:12 MHDA- 2023/06/14 06:42 PMCR- 2023/06/12 CRDT- 2023/06/12 15:23 PHST- 2023/06/14 06:42 [medline] PHST- 2023/06/12 19:12 [pubmed] PHST- 2023/06/12 15:23 [entrez] PHST- 2023/06/12 00:00 [pmc-release] AID - 202219790 [pii] AID - 10.1073/pnas.2219790120 [doi] PST - ppublish SO - Proc Natl Acad Sci U S A. 2023 Jun 20;120(25):e2219790120. doi: 10.1073/pnas.2219790120. Epub 2023 Jun 12.