FADD and the NF-kappaB family member Bcl-3 regulate complementary pathways to control T-cell survival and proliferation.
Fas-associated protein with death domain/mediator of receptor induced toxicity (FADD/MORT1) was first described as a transducer of death receptor signalling but was later recognized also to be important for proliferation of T cells. B-cell lymphoma 3 (Bcl-3) is a relatively little understood member of the nuclear factor (NF)-kappaB family of transcription factors. We recently found that Bcl-3 is up-regulated in T cells from mice where FADD function is blocked by a dominant negative transgene (FADD-DN). To understand the importance of this, we generated FADD-DN/bcl-3(-/-) mice. Here, we report that T cells from these mice show massive cell death and severely reduced proliferation in response to T-cell receptor (TCR) stimulation in vitro. Transgenic co-expression of Bcl-2 (FADD-DN/bcl-3(-/-)/vav-bcl-2 mice) rescued the survival but not the proliferation of T cells. FADD-DN/bcl-3(-/-) mice had normal thymocyte numbers but reduced numbers of peripheral T cells despite an increase in cycling T cells in vivo. However, activation of the classical NF-kappaB and extracellular regulated kinase (ERK) pathways and expression of interleukin (IL)-2 mRNA upon stimulation were normal in T cells from FADD-DN/bcl-3(-/-) mice. These data suggest that FADD and Bcl-3 regulate separate pathways that both contribute to survival and proliferation in mouse T cells.
Institute for Medical Microbiology, Technische Universität München, Munich, Germany.
Svetla
S
Rangelova
Susanne
S
Kirschnek
Andreas
A
Strasser
Georg
G
Häcker
D000818:Animals; D000081242:B-Cell Lymphoma 3 Protein; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D053200:Fas-Associated Death Domain Protein / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D000081242:B-Cell Lymphoma 3 Protein; C000631345:Bcl3 protein, mouse; D053200:Fas-Associated Death Domain Protein; D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D011948:Receptors, Antigen, T-Cell; D014157:Transcription Factors