Disruption of NF-kappa B signaling and chemokine gene activation by retroviral mediated expression of IKK gamma/NEMO mutants.
Phosphorylation of I kappa Bs--the cytoplasmic inhibitors of the NF-kappa B transcription factors--is the key event which triggers activation of the NF-kappa B cascade. Signal-mediated phosphorylation of I kappa B alpha is mediated by a multiprotein complex, the I kappa B kinase (IKK) complex, which is composed of at least three identified subunits. Two of these polypeptides, IKK alpha and IKK beta, also known as IKK1 and IKK2, are the catalytic subunits of the kinase complex and phosphorylate I kappa B alpha and I kappa B beta. The third component, NEMO/IKK gamma, does not exhibit kinase activity, but rather constitutes a regulatory subunit. In the present study, C-terminal truncated forms of IKK gamma--Delta C-IKK gamma 306 and Delta C-IKK gamma 261--were stably expressed in the myeloid cell line U937 by retroviral-mediated gene transfer. Overexpression of Delta C-IKK gamma resulted in a reduction in IKK kinase activity in vitro, a subsequent decrease in NF-kappa B DNA binding activity, and inhibition of chemokine gene induction in response to TNFalpha stimulation or paramyxovirus infection. This study demonstrates the efficacy of Delta C-IKK gamma as a repressor of IKK signaling and NF-kappa B activation and suggests a potential gene therapy approach to limit chronic inflammation due to chemokine hyperactivation.
Le Page
C
C
Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, McGill University, Montreal. H3T 1E2, Canada
Popescu
O
O
Génin
P
P
Lian
J
J
Paquin
A
A
Galipeau
J
J
Hiscott
J
J
D015153:Blotting, Western; D002352:Carrier Proteins; D002460:Cell Line; D018925:Chemokines / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D051550:I-kappa B Kinase; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics*; D015398:Signal Transduction; D015533:Transcriptional Activation; D014161:Transduction, Genetic; D014162:Transfection; D020298:U937 Cells
D002352:Carrier Proteins; D018925:Chemokines; C491731:IKBKG protein, human; D016328:NF-kappa B; D010770:Phosphotransferases; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; D020928:Mitogen-Activated Protein Kinases