title: Distinct pathways generate peptides from defective ribosomal products for CD8+ T cell immunosurveillance.
abstract: To understand better the endogenous sources of MHC class I peptide ligands, we generated an antigenic reporter protein whose degradation is rapidly and reversibly controlled with Shield-1, a cell-permeant drug. Using this system, we demonstrate that defective ribosomal products (DRiPs) represent a major and highly efficient source of peptides and are completely resistant to our attempts to stabilize the protein. Although peptides also derive from nascent Shield-1-sensitive proteins and "retirees" created by Shield-1 withdrawal, these are much less efficient sources on a molar basis. We use this system to identify two drugs--each known to inhibit polyubiquitin chain disassembly--that selectively inhibit presentation of Shield-1-resistant DRiPs. These findings provide the initial evidence for distinct biochemical pathways for presentation of DRiPs versus retirees and implicate polyubiquitin chain disassembly or the actions of deubiquitylating enzymes as playing an important role in DRiP presentation.
authors.affiliation: Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Dolan
authors.forename: Lily
authors.initials: L
authors.lastname: Li
authors.forename: Charles A
authors.initials: CA
authors.lastname: Veltri
authors.forename: Chris M
authors.initials: CM
authors.lastname: Ireland
authors.forename: Jack R
authors.initials: JR
authors.lastname: Bennink
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Yewdell
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D005260:Female; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006183:H-2 Antigens / Q000096:biosynthesis / Q000235:genetics; D007157:Immunologic Surveillance / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009025:Morpholines / Q000494:pharmacology; D010047:Ovalbumin / Q000276:immunology / Q000378:metabolism; D010452:Peptide Biosynthesis / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D055550:Protein Stability / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000096:biosynthesis* / Q000172:deficiency* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D009025:Morpholines; C110366:OVA-8; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; C540198:Shield-1 compound; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D010047:Ovalbumin