title: Rad23 as a reciprocal agent for stimulating or repressing immune responses.
abstract: The proteasome degrades cellular proteins and provides peptides for major histocompatibility complex (MHC) class I molecules to drive CD8+ T-cell responses to kill intracellular pathogens. Rad23 plays a role in protein degradation by targeting polyubiquitinated substrates to the proteasome via an N-terminal ubiquitin-like (UbL) domain that binds the proteasome and two C-terminal ubiquitin-associated (UBA) domains that bind ubiquitinated proteins. We demonstrate here that fusion of Rad23 or its UBA domain to the green fluorescent protein (GFP) targets this antigen to the proteasome for increased degradation in mammalian cells and enhanced antigen-specific CD8+ T-cell responses in BALB/c mice. Conversely, we show that coexpression of unfused Rad23 with destabilized GFP inhibits degradation of the reporter protein and attenuates in vivo CD8+ T-cell responses. Rad23 therefore holds promise as a useful agent either to enhance or attenuate cellular immune responses to suit the reciprocal immunologic needs of both gene therapy and genetic vaccine applications.
authors.affiliation: Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital, and Texas Children's Hospital, Houston, TX 77030, USA.
authors.forename: Helen A
authors.initials: HA
authors.lastname: Andersson
authors.forename: Marco F
authors.initials: MF
authors.lastname: Passeri
authors.forename: Michael A
authors.initials: MA
authors.lastname: Barry
mesh_terms: D000818:Animals; D015153:Blotting, Western; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D045744:Cell Line, Tumor; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D034801:Mastocytoma / Q000473:pathology; D008561:Membrane Fusion; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D010957:Plasmids; D011233:Precipitin Tests; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000378:metabolism*; D019076:Transgenes; D025801:Ubiquitin / Q000378:metabolism; D019444:Vaccines, DNA
chemical_list: D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D025801:Ubiquitin; D019444:Vaccines, DNA; D049452:Green Fluorescent Proteins; C086985:RAD23A protein, human; D046988:Proteasome Endopeptidase Complex; D045643:DNA Repair Enzymes