Induction of TNF receptor I-mediated apoptosis via two sequential signaling complexes.
Level 5 - mechanism / opinion, no new human data
In vitro mechanistic research (CEBM Level 5).
PubMed 12887920 · doi:10.1016/s0092-8674(03)00521-x
What was done
Investigated the molecular mechanism governing the cell death versus survival decision downstream of TNF-receptor I (TNFR1) by characterizing the formation and composition of sequential receptor-associated protein complexes.
What was found
TNFR1 signaling was shown to occur through two sequential complexes. Complex I forms at the plasma membrane (containing TNFR1, TRADD, RIP1, and TRAF2) and rapidly activates NF-kappa B. TRADD and RIP1 subsequently associate with FADD and caspase-8 to form complex II in the cytoplasm. Successful NF-kappa B activation by complex I leads to incorporation of the caspase-8 inhibitor FLIP(L) into complex II to promote survival; failure to activate NF-kappa B allows complex II to trigger apoptosis. No numerical values or statistics were reported in the abstract.
Why it matters
This study defines the classic two-complex checkpoint model of TNFR1 signal transduction, explaining how cells temporally arbitrate between pro-survival NF-kappa B signaling and apoptotic cell death.
Limits
The abstract describes qualitative molecular pathways without quantitative metrics, effect sizes, or variance. Cell lines, experimental sample sizes, and in vivo applicability are not specified in the abstract.
Cited by
- supports TNF receptors can initiate either a survival signal or a cell death/suicide signal depending on the cellular context.