Notch3 and pre-TCR interaction unveils distinct NF-kappaB pathways in T-cell development and leukemia.
Notch signaling plays a critical role in T-cell differentiation and leukemogenesis. We previously demonstrated that, while pre-TCR is required for thymocytes proliferation and leukemogenesis, it is dispensable for thymocyte differentiation in Notch3-transgenic mice. Notch3-transgenic premalignant thymocytes and T lymphoma cells overexpress pTalpha/pre-TCR and display constitutive activation of NF-kappaB, providing survival signals for immature thymocytes. We provide genetic and biochemical evidence that Notch3 triggers multiple NF-kappaB activation pathways. A pre-TCR-dependent pathway preferentially activates NF-kappaB via IKKbeta/IKKalpha/NIK complex, resulting in p50/p65 heterodimer nuclear entry and recruitment onto promoters of Cyclin D1, Bcl2-A1 and IL7-receptor-alpha genes. In contrast, upon pTalpha deletion, Notch3 binds IKKalpha and maintains NF-kappaB activation through an alternative pathway, depending on an NIK-independent IKKalpha homodimer activity. The consequent NF-kappaB2/p100 processing allows nuclear translocation of p52/RelB heterodimers, which only trigger transcription from Bcl2-A1 and IL7-receptor-alpha genes. Our data suggest that a finely tuned interplay between Notch3 and pre-TCR pathways converges on regulation of NF-kappaB activity, leading to differential NF-kappaB subunit dimerization that regulates distinct gene clusters involved in either cell differentiation or proliferation/leukemogenesis.
Department of Experimental Medicine and Pathology, University La Sapienza, Roma, Italy.
Alessandra
A
Vacca
Maria Pia
MP
Felli
Rocco
R
Palermo
Giuseppina
G
Di Mario
Angelica
A
Calce
Monica
M
Di Giovine
Luigi
L
Frati
Alberto
A
Gulino
Isabella
I
Screpanti
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D019938:Cyclin D1 / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D051550:I-kappa B Kinase / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D007938:Leukemia / Q000378:metabolism* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D052003:NF-kappa B p52 Subunit / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D000071656:Receptor, Notch3; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D020395:Receptors, Interleukin-7 / Q000378:metabolism; D051880:Receptors, Notch / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000502:physiology*; D013950:Thymus Gland / Q000378:metabolism; D051996:Transcription Factor RelA / Q000378:metabolism; D051841:Transcription Factor RelB / Q000378:metabolism; D000097782:NF-kappaB-Inducing Kinase
D019938:Cyclin D1; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D008562:Membrane Glycoproteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D052003:NF-kappa B p52 Subunit; D017346:Protein Serine-Threonine Kinases; D019253:Proto-Oncogene Proteins c-bcl-2; D000071656:Receptor, Notch3; D016693:Receptors, Antigen, T-Cell, alpha-beta; D020395:Receptors, Interleukin-7; D051880:Receptors, Notch; D051996:Transcription Factor RelA; D051841:Transcription Factor RelB; D000097782:NF-kappaB-Inducing Kinase; C000606205:Nfkbia protein, mouse; C499373:Notch3 protein, mouse; C090377:pre-T cell receptor alpha; C496562:Ikbkb protein, mouse