RT Journal Article SR Electronic T1 Control of I kappa B-alpha proteolysis by site-specific, signal-induced phosphorylation JF Science JO Science FD American Association for the Advancement of Science SP 1485 OP 1488 DO 10.1126/science.7878466 VO 267 IS 5203 A1 Brown, K A1 Gerstberger, S A1 Carlson, L A1 Franzoso, G A1 Siebenlist, U YR 1995 UL http://science.sciencemag.org/content/267/5203/1485.abstract AB 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.