Inhibition of SRC tyrosine kinases suppresses activation of nuclear factor-kappaB, and serine and tyrosine phosphorylation of IkappaB-alpha in lipopolysaccharide-stimulated raw 264.7 macrophages.
Involvement of protein tyrosine kinases (PTK) in lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-kappaB) activation has been demonstrated. Studies investigated the role of PTK and the underlying mechanisms by which PTK play a role in LPS induction of pathways leading to NF-kappaB activation in macrophages. Inhibitors of PTK-genistein, herbimycin A, or AG126-blocked LPS-induced NF-kappaB activation. Genistein also blocked pervanadate-induced NF-kappaB activation. Furthermore, Src TK selective inhibitors-damnacanthal or PP1-blocked LPS-induced NF-kappaB activation over a range of nanomolar concentrations. Genistein, damnacanthal, or PP1 blocked the LPS-induced serine phosphorylation, the degradation of IkappaB-alpha, and the consequent translocation of the p65 subunit of NF-kappaB to the nucleus. In addition to serine phosphorylation of IkappaB-alpha, LPS-induced NF-kappaB activation also required tyrosine phosphorylation of IkappaB-alpha. These TK inhibitors blocked substantially LPS induction of tyrosine phosphorylation of IkappaB-alpha. Furthermore, cSrc and Lck were physically associated with IkappaB-alpha. These results suggest that the LPS-induced NF-kappaB pathways are dependent on both serine and tyrosine phosphorylation of IkappaB-alpha, and that Src TK, such as cSrc and Lck, are key components of the LPS signaling pathway through at least two different mechanisms associated with NF-kappaB activation.
Kang
Jihee Lee
JL
Department of Physiology, College of Medicine, Division of Cell Biology, Ewha Medical Research Center, Ewha Womans University, Seoul, Korea. jihee@ewha.ac.kr
Lee
Hye Won
HW
Kim
Hee Jae
HJ
Lee
Hui Su
HS
Castranova
Vincent
V
Lim
Chae-Man
CM
Koh
Younsuck
Y
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D004926:Escherichia coli; D020672:I-kappa B Proteins / Q000378:metabolism* / Q000494:pharmacology; D047468:Immunoprecipitation; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D012694:Serine / Q000494:pharmacology; D013268:Stimulation, Chemical; D014443:Tyrosine / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D000072000:NF-KappaB Inhibitor alpha; D014443:Tyrosine; D012694:Serine; D019061:src-Family Kinases