A serine/threonine kinase activity is closely associated with a 65-kDa phosphoprotein specifically recognized by the kappa B enhancer element.
The immunoglobulin kappa light chain enhancer, kappa B, is an important cis-acting transcriptional element. kappa B binds a number of proteins including the members of the ubiquitous NF-kappa B family of transcription factors. Agarose beads coupled to a double-stranded oligonucleotide containing the kappa B motif were used to isolate a 65-kDa predominantly nuclear phosphoprotein. Southwestern blot analysis demonstrated that this phosphoprotein can bind the kappa B element directly and specifically. This kappa B-associated protein was phosphorylated in vivo and in vitro by a nuclear serine/threonine kinase(s) which, in a number of different cell lines, appeared to be stimulated in response to interleukin-1 alpha and lipopolysaccharide treatment. In the B cell lines 70Z/3 and CH12 LX2B, and the T cell line EL-4 6.1 C10 the activity of the kappa B-associated kinase(s) correlated with the binding activity of nuclear NF-kappa B displayed in a gel shift assay. In vitro, the 65-kDa protein was phosphorylated in the absence of exogenously added kinase. The 65-kDa phosphoprotein and the kinase activity remained associated following sequential anion-exchange and hydrophobic interaction chromatography. These results suggest that the kappa B-associated phosphoprotein is either autophosphorylated or is phosphorylated by a closely associated kinase(s). Stimulation of a nuclear protein kinase which is closely associated with a sequence-specific DNA may reflect a novel mechanism by which growth factors regulate gene expression.
Ostrowski
J
J
Department of Medicine, University of Washington, Seattle 98195.
Sims
J E
JE
Sibley
C H
CH
Valentine
M A
MA
Dower
S K
SK
Meier
K E
KE
Bomsztyk
K
K
D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D002853:Chromatography, Liquid; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D013379:Substrate Specificity
D004268:DNA-Binding Proteins; D007375:Interleukin-1; D010750:Phosphoproteins; D004247:DNA; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases