Human Notch-1 inhibits NF-kappa B activity in the nucleus through a direct interaction involving a novel domain.
Notch participates in diverse cell fate decisions throughout embryonic development and postnatal life. Members of the NF-kappaB/Rel family of transcription factors are involved in the regulation of a variety of genes important for immune function. The biological activity of the NF-kappaB transcription factors is controlled by IkappaB proteins. Our previous work demonstrated that an intracellular, constitutively active form of human Notch-1/translocation-associated Notch homologue-1 (Notch(IC)) functions as an IkappaB molecule with specificity for the NF-kappaB p50 subunit and physically interacts with NF-kappaB in T cells. In the current study, we investigated the roles of different domains of Notch(IC) in the regulation of NF-kappaB-directed gene expression and NF-kappaB DNA binding activity. We found that Notch(IC) localizes to the nucleus and that a region in the N-terminal portion of Notch(IC), not the six ankyrin repeats, is responsible for the inhibitory effects of Notch on NF-kappaB-directed gene expression and NF-kappaB DNA binding activity. The N-terminal portion of Notch(IC) inhibited p50 DNA binding and interacted specifically with p50 subunit, not p65 of NF-kappaB. The interaction between Notch and NF-kappaB indicates that in addition to its role in the development of the immune system, Notch-1 may also have critical functions in the immune response, inflammation, viral infection, and apoptosis through control of NF-kappaB-mediated gene expression.
Wang
J
J
Laboratory of Gene Regulation, Division of Therapeutic Proteins, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. wangj@cber.fda.gov
Shelly
L
L
Miele
L
L
Boykins
R
R
Norcross
M A
MA
Guan
E
E
D000595:Amino Acid Sequence; D001667:Binding, Competitive / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation / Q000235:genetics; D005822:Genetic Vectors / Q000494:pharmacology; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism / Q000502:physiology; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000502:physiology; D052002:NF-kappa B p50 Subunit; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins / Q000494:pharmacology; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; C497761:NOTCH1 protein, human; D010446:Peptide Fragments; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D014157:Transcription Factors