Vav synergizes with protein kinase C theta to mediate IL-4 gene expression in response to CD28 costimulation in T cells.
The secretion of IL-4, which displays many important immunoregulatory functions, is restricted to cells of the Th2 subtype. In this study, we investigated the early signaling events leading to the activation of IL-4 transcription. Vav, the protein kinase C (PKC) isoform theta, and the adaptor protein SLP76 (SH2-domain-containing leukocyte protein of 76 kDa), induced transcription from the IL-4 promoter. Vav and PKC theta synergistically activated human IL-4 promoter transcription and IL-4 mRNA production and were found to be constitutively associated in vivo. CD3/CD28-induced IL-4 transcription was inhibited upon coexpression of dominant negative forms of Vav, the adaptor proteins LAT (linker for activation of T cells) and SLP76, PKC theta, and components of the pathways leading to the activation of c-Jun N-terminal kinase (mitogen-activated protein kinase kinase 7 (MKK7), mixed lineage kinase 3 (MLK3)) and NF-kappa B (I kappa B kinase alpha and I kappa B kinase beta). The Vav/PKC theta-mediated synergistic activation of IL-4 transcription was not inhibited by cyclosporin A. Three independent experimental approaches revealed that Vav/PKC theta-derived signals selectively target the P1 and positive regulatory element (PRE)-I elements contained within the human IL-4 promoter. Vav/PKC theta strongly activated a luciferase reporter construct controlled by trimerized P1 or PRE-I elements and furthermore stimulated DNA binding of nuclear proteins to the P1 and PRE-I elements. Vav/PKC theta-induced transcription from the IL-4 promoter was almost completely abrogated by mutation of either the P1 or the PRE-I element within the entire IL-4 promoter.
Hehner
S P
SP
Tumor Immunology Program, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Li-Weber
M
M
Giaisi
M
M
Dröge
W
W
Krammer
P H
PH
Schmitz
M L
ML
D018106:CD28 Antigens / Q000502:physiology*; D018797:Cell Cycle Proteins; D004357:Drug Synergism; D004742:Enhancer Elements, Genetic / Q000276:immunology; D004789:Enzyme Activation / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics*; D007527:Isoenzymes / Q000378:metabolism / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000276:immunology; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology*; D000074121:Protein Kinase C-theta; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051567:Proto-Oncogene Proteins c-vav; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D014158:Transcription, Genetic / Q000276:immunology
D018106:CD28 Antigens; D018797:Cell Cycle Proteins; D007527:Isoenzymes; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; C496618:VAV1 protein, human; D015847:Interleukin-4; C076233:PRKCQ protein, human; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases