title: CD2 signalling induces phosphorylation of CREB in primary lymphocytes.
abstract: Promoter sequences responsive to cyclic AMP (cAMP) are found in a number of cellular genes, and bind transcription factors of the cAMP response element binding protein (CREB)/activating transcription factor-1 (ATF-1) family. We have used a human T-lymphotropic virus type 1 (HTLV-1) model of cAMP response element (CRE) transcription to investigate the influence of lymphocyte activation on transcription from homologous regions in the viral promoter. We previously demonstrated increased HTLV-1 transcription following CD2 but not CD3 receptor cross-linking. We hypothesized that this increased viral transcription was mediated, in part, through the phosphorylation of CREB. Therefore, we investigated CD2 and CD3 receptor-mediated signalling in primary human peripheral blood mononuclear cells (PBMC). CD2, but not CD3, cross-linking increased cAMP detected by competitive enzyme-linked immunosorbent assay (ELISA) approximately fourfold. CD2 cross-linking concurrently increased phosphorylation of CREB detected by immunoblot assay eightfold. Consistent with post-translational regulation, no change in total level of CREB protein was observed. Phosphorylation of CREB occurred through a herbimycin A and Rp-cAMP-sensitive pathway, suggesting phosphorylation required antecedent activation of both protein tyrosine kinases (PTK) and protein kinase A (PKA). Both CD2 and CD3 cross-linking increased binding of nuclear proteins to a radiolabelled CRE oligonucleotide probe in electrophoretic mobility shift assays suggesting that lymphocyte activation enhances binding independently of phosphorylation of CREB at serine 133. These data indicate specific modulation of the CREB/ATF-1 family of transcription factors by the CD2 signalling pathway and suggest CD2 receptor modulation of CRE-mediated transcription following ligand engagement (e.g. cell-to-cell contact).
authors.affiliation: Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Ohio State University, Columbus Ohio, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Guyot
authors.forename: G C
authors.initials: GC
authors.lastname: Newbound
authors.forename: M D
authors.initials: MD
authors.lastname: Lairmore
mesh_terms: D051698:Activating Transcription Factor 2; D016227:Benzoquinones; D015153:Blotting, Western; D018801:CD2 Antigens / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004586:Electrophoresis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015368:Human T-lymphotropic virus 1 / Q000502:physiology*; D006801:Humans; D047029:Lactams, Macrocyclic; D008213:Lymphocyte Activation / Q000502:physiology*; D009000:Monocytes / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D015345:Oligonucleotide Probes; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011809:Quinones / Q000494:pharmacology; D020239:Receptor Cross-Talk; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D051698:Activating Transcription Factor 2; D016227:Benzoquinones; D018801:CD2 Antigens; D017252:CD3 Complex; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D009281:Naphthalenes; D015345:Oligonucleotide Probes; D047428:Protein Kinase Inhibitors; D011809:Quinones; D013873:Thionucleotides; D014157:Transcription Factors; D017828:Rifabutin; C016957:adenosine-3',5'-cyclic phosphorothioate; C020754:herbimycin; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; C058819:calphostin C