Notch1 augments NF-kappaB activity by facilitating its nuclear retention.
Notch1 specifically upregulates expression of the cytokine interferon-gamma in peripheral T cells through activation of NF-kappaB. However, how Notch mediates NF-kappaB activation remains unclear. Here, we examined the temporal relationship between Notch signaling and NF-kappaB induction during T-cell activation. NF-kappaB activation occurs within minutes of T-cell receptor (TCR) engagement and this activation is sustained for at least 48 h following TCR signaling. We used gamma-secretase inhibitor (GSI) to prevent the cleavage and subsequent activation of Notch family members. We demonstrate that GSI blocked the later, sustained NF-kappaB activation, but did not affect the initial activation of NF-kappaB. Using biochemical approaches, as well as confocal microscopy, we show that the intracellular domain of Notch1 (N1IC) directly interacts with NF-kappaB and competes with IkappaBalpha, leading to retention of NF-kappaB in the nucleus. Additionally, we show that N1IC can directly regulate IFN-gamma expression through complexes formed on the IFN-gamma promoter. Taken together, these data suggest that there are two 'waves' of NF-kappaB activation: an initial, Notch-independent phase, and a later, sustained activation of NF-kappaB, which is Notch dependent.
Shin
Hyun Mu
HM
Molecular and Cellular Biology Program, University of Massachusetts/Amherst, Amherst, MA 01003, USA.
Minter
Lisa M
LM
Cho
Ok Hyun
OH
Gottipati
Sridevi
S
Fauq
Abdul H
AH
Golde
Todd E
TE
Sonenshein
Gail E
GE
Osborne
Barbara A
BA
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D018106:CD28 Antigens / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism*; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D020672:I-kappa B Proteins / Q000378:metabolism*; D007371:Interferon-gamma / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000032:analysis / Q000378:metabolism*; D052002:NF-kappa B p50 Subunit / Q000235:genetics; D011401:Promoter Regions, Genetic; D020569:Proto-Oncogene Proteins c-rel / Q000235:genetics; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000906:Antibodies; D018106:CD28 Antigens; D017252:CD3 Complex; C485468:Cd3e protein, mouse; D020672:I-kappa B Proteins; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; C000606205:Nfkbia protein, mouse; C497762:Notch1 protein, mouse; D020569:Proto-Oncogene Proteins c-rel; D051881:Receptor, Notch1; D000072000:NF-KappaB Inhibitor alpha; D007371:Interferon-gamma