Control of I kappa B-alpha proteolysis by site-specific, signal-induced phosphorylation.
I kappa B-alpha inhibits transcription factor NF-kappa B by retaining it in the cytoplasm. Various stimuli, typically those associated with stress or pathogens, rapidly inactivate I kappa B-alpha. This liberates NF-kappa B to translocate to the nucleus and initiate transcription of genes important for the defense of the organism. Activation of NF-kappa B correlates with phosphorylation of I kappa B-alpha and requires the proteolysis of this inhibitor. When either serine-32 or serine-36 of I kappa B-alpha was mutated, the protein did not undergo signal-induced phosphorylation or degradation, and NF-kappa B could not be activated. These results suggest that phosphorylation at one or both of these residues is critical for activation of NF-kappa B.
Brown
K
K
National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1876.
Gerstberger
S
S
Carlson
L
L
Franzoso
G
G
Siebenlist
U
U
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins; D015759:Ionomycin / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D015398:Signal Transduction; D013601:T-Lymphocytes; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D015759:Ionomycin; D013755:Tetradecanoylphorbol Acetate