Searching for proteins that interact with the ectodomain of CLEC9A, the critical cDC1 receptor involved in binding exposed actin on dead cells, Tullet and Tan et al. found that RNF41, a highly conserved ubiquitin ligase, bound CLEC9A in biochemical assays and in cells. Genetic knockdown revealed a regulatory role for RNF41 in antigen presentation. Ubiquitination by the RING-domain of RNF41 resulted in downmodulation of CLEC9A at steady state, but binding to actin from dead cells abrogated that regulation and shifted the path of dead cell antigen-loaded CLEC9A to early endosomes for presentation.
Contributed by Ed Fritsch
ABSTRACT: The dendritic cell receptor Clec9A facilitates processing of dead cell-derived antigens for cross-presentation and the induction of effective CD8(+) T cell immune responses. Here, we show that this process is regulated by E3 ubiquitin ligase RNF41 and define a new ubiquitin-mediated mechanism for regulation of Clec9A, reflecting the unique properties of Clec9A as a receptor specialized for delivery of antigens for cross-presentation. We reveal RNF41 is a negative regulator of Clec9A and the cross-presentation of dead cell-derived antigens by mouse dendritic cells. Intriguingly, RNF41 regulates the downstream fate of Clec9A by directly binding and ubiquitinating the extracellular domains of Clec9A. At steady-state, RNF41 ubiquitination of Clec9A facilitates interactions with ER-associated proteins and degradation machinery to control Clec9A levels. However, Clec9A interactions are altered following dead cell uptake to favor antigen presentation. These findings provide important insights into antigen cross-presentation and have implications for development of approaches to modulate immune responses.
Author Info: (1) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (2) Infectio
Author Info: (1) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (2) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (3) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (4) Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (5) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (6) Centre for Biomedical Research, Burnet Institute, Melbourne, Australia. (7) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (8) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (9) Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (10) Monash Micro Imaging Facility, Monash University, Clayton, Australia. (11) Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Australia. (12) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (13) Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia. (14) Department of Biochemistry and Molecular Biology at the Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia. (15) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Australia. (16) Mater Research Institute - University of Queensland, Translational Research Institute, Brisbane, Australia. (17) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia. (18) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (19) Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia. Department of Biochemistry and Molecular Biology at the Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia. (20) Department of Immunology, Monash University, Melbourne, Australia. (21) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (22) Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia. (23) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (24) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia. (25) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (26) The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia. Department of Medical Biology, University of Melbourne, Parkville, Australia. (27) Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
