title: Endoplasmic reticulum stress regulator XBP-1 contributes to effector CD8+ T cell differentiation during acute infection.
abstract: The transcription factor X-box-binding protein-1 (XBP-1) plays an essential role in activating the unfolded protein response in the endoplasmic reticulum (ER). Transcribed XBP-1 mRNA is converted to its active form by unconventional cytoplasmic splicing mediated by inositol-requiring enzyme-1 (IRE-1) upon ER stress. We report activation of the IRE-1/XBP-1 pathway in effector CD8(+) T cells during the response to acute infection. Transcription of unspliced XBP-1 mRNA is up-regulated by IL-2 signals, while its splicing is induced after TCR ligation. Splicing of XBP-1 mRNA was evident during the expansion of Ag-specific CD8(+) T cells in response to viral or bacterial infection. An XBP-1 splicing reporter revealed that splicing activity was enriched in terminal effector cells expressing high levels of killer cell lectin-like receptor G1 (KLRG1). Overexpression of the spliced form of XBP-1 in CD8(+) T cells enhanced KLRG1 expression during infection, whereas XBP-1(-/-) CD8(+) T cells or cells expressing a dominant-negative form of XBP-1 showed a decreased proportion of KLRG1(high) effector cells. These results suggest that, in the response to pathogen, activation of ER stress sensors and XBP-1 splicing contribute to the differentiation of end-stage effector CD8(+) T cells.
authors.affiliation: Department of Immunology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kamimura
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bevan
mesh_terms: D000208:Acute Disease; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D037181:Lectins, C-Type; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D000071701:Regulatory Factor X Transcription Factors; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology; D000071717:X-Box Binding Protein 1
chemical_list: D000942:Antigens, Bacterial; D004268:DNA-Binding Proteins; C451496:Klrg1 protein, mouse; D037181:Lectins, C-Type; D008565:Membrane Proteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605544:Xbp1 protein, mouse; C486556:Ern2 protein, mouse; D017346:Protein Serine-Threonine Kinases