Requirement of phosphatidylinositol 3-kinase activity for bradykinin stimulation of NF-kappaB activation in cultured human epithelial cells.
The signaling mechanisms utilized by bradykinin (BK) to activate the transcription factor nuclear factor kappaB (NF-kappaB) are poorly defined. We previously demonstrated that BK-stimulated NF-kappaB activation requires the small GTPase RhoA. We present evidence that BK-induced NF-kappaB activation both activates and requires phosphatidylinositol 3-kinase (PI 3-kinase) in A549 human epithelial cells. Pre-treatment with the PI 3-kinase-specific inhibitors, wortmannin, and LY294002 effectively blocked BK-induced PI 3-kinase activity. Wortmannin and LY294002 also abolished BK-induced NF-kappaB activation, as did transient transfection with a dominant negative mutant of the p85 subunit. BK-stimulated PI 3-kinase activity and NF-kappaB activation were sensitive to pertussis but not cholera toxin, suggesting that the B2 BK receptors transducing the response were coupled to Galphai or Galphao heterotrimeric G proteins. Tumor necrosis factor alpha (TNFalpha) also stimulated increased PI 3-kinase activity, however TNFalpha-stimulated NF-kappaB activation was not affected by the PI 3-kinase inhibitors or the p85 dominant negative mutant. These findings provide evidence that BK-induced NF-kappaB activation utilizes a signaling pathway that requires activity of both RhoA and PI 3-kinase and is distinct from the signaling pathway utilized by TNFalpha. Furthermore, we show that the p85 regulatory subunit is required for activation of PI 3-kinase activity by this G protein-coupled receptor.
Pan
Z K
ZK
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
Christiansen
S C
SC
Ptasznik
A
A
Zuraw
B L
BL
D000230:Adenocarcinoma / Q000201:enzymology; D000730:Androstadienes / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology*; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D000077191:Wortmannin
D000730:Androstadienes; D001920:Bradykinin; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D010566:Virulence Factors, Bordetella; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one