Interleukin-4 signals regulating CD23 gene expression in human B cells: protein kinase C-independent signaling pathways.
Signal transduction by IL-4 leading to the activation of CD23(Fc epsilon RII) gene expression using human tonsillar B cells was studied. IL-4 stimulated CD23 mRNA transcription within hours (1-4 hr) which preceded the later induction of cell surface CD23. The induction of CD23 gene transcription by IL-4 was not adversely affected by cycloheximide, suggesting that post-translational modifications are accounted for the gene activation. PKC activators (PMA, diacylglycerol, indolactam) were effective inducers of CD23 gene expression, whereas calcium ionophores were not. PMA and IL-4 also displayed similar induction kinetics for CD23 mRNA. However, the signaling pathways utilized by the two agents appear distinct as shown by (1) cotreatment of IL-4 and PMA caused CD23 gene expression over the maximum level inducible by each agent alone and (2) unlike the PMA-induced CD23 expression, the IL-4-induced expression was not affected by PKC inhibitors. These results strongly suggest that IL-4 signals leading to CD23 gene activation are mediated via a PKC-independent pathway. A possible role of tyrosine kinases in the regulation of CD23 expression is discussed.
Lee
C E
CE
Immunology Research Laboratory, Genetic Engineering Research Institute, KIST, Taejon, Korea.
Yoon
S R
SR
Pyun
K H
KH
D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured / Q000187:drug effects; D004075:Diglycerides / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology*; D014066:Palatine Tonsil / Q000166:cytology; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C; D011505:Protein-Tyrosine Kinases; D017455:Receptors, IgE / Q000235:genetics*; D015398:Signal Transduction; D015533:Transcriptional Activation
D004075:Diglycerides; D010703:Phorbol Esters; D017455:Receptors, IgE; D015847:Interleukin-4; D007073:Immunoglobulin E; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C