Activation of NF-kappa B by bradykinin through a Galpha(q)- and Gbeta gamma-dependent pathway that involves phosphoinositide 3-kinase and Akt.
Recent work has suggested a role for the serine/threonine kinase Akt and IkappaB kinases (IKKs) in nuclear factor (NF)-kappaB activation. In this study, the involvement of these components in NF-kappaB activation through a G protein-coupled pathway was examined using transfected HeLa cells that express the B2-type bradykinin (BK) receptor. The function of IKK2, and to a lesser extent, IKK1, was suggested by BK-induced activation of their kinase activities and by the ability of their dominant negative mutants to inhibit BK-induced NF-kappaB activation. BK-induced NF-kappaB activation and IKK2 activity were markedly inhibited by RGS3T, a regulator of G protein signaling that inhibits Galpha(q), and by two Gbetagamma scavengers. Co-expression of Galpha(q) potentiated BK-induced NF-kappaB activation, whereas co-expression of either an activated Galpha(q)(Q209L) or Gbeta(1)gamma(2) induced IKK2 activity and NF-kappaB activation without BK stimulation. BK-induced NF-kappaB activation was partially blocked by LY294002 and by a dominant negative mutant of phosphoinositide 3-kinase (PI3K), suggesting that PI3K is a downstream effector of Galpha(q) and Gbeta(1)gamma(2) for NF-kappaB activation. Furthermore, BK could activate the PI3K downstream kinase Akt, whereas a catalytically inactive mutant of Akt inhibited BK-induced NF-kappaB activation. Taken together, these findings suggest that BK utilizes a signaling pathway that involves Galpha(q), Gbeta(1)gamma(2), PI3K, Akt, and IKK for NF-kappaB activation.
Xie
P
P
Departments of Pharmacology and Molecular Genetics, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA.
Browning
D D
DD
Hay
N
N
Mackman
N
N
Ye
R D
RD
D019943:Amino Acid Substitution; D001920:Bradykinin / Q000494:pharmacology*; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006367:HeLa Cells; D020962:Heterotrimeric GTP-Binding Proteins; D006801:Humans; D051550:I-kappa B Kinase; D007375:Interleukin-1 / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D001920:Bradykinin; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins; D051550:I-kappa B Kinase; D007375:Interleukin-1; D008156:Luciferases; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; C118981:G-protein Beta gamma; C494918:AKT1 protein, human; C496559:CHUK protein, human; C496560:IKBKB protein, human; C496565:IKBKE protein, human