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A revised model of TRAIL ‐R2 DISC assembly explains how FLIP (L) can inhibit or promote apoptosis
Author(s) -
Humphreys Luke M,
Fox Jennifer P,
Higgins Catherine A,
Majkut Joanna,
Sessler Tamas,
McLaughlin Kirsty,
McCann Christopher,
Roberts Jamie Z,
Crawford Nyree T,
McDade Simon S,
Scott Christopher J,
Harrison Timothy,
Longley Daniel B
Publication year - 2020
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201949254
Subject(s) - microbiology and biotechnology , apoptosis , chemistry , biology , biochemistry
The long FLIP splice form FLIP (L) can act as both an inhibitor and promoter of caspase‐8 at death‐inducing signalling complexes ( DISC s) formed by death receptors such as TRAIL ‐R2 and related intracellular complexes such as the ripoptosome. Herein, we describe a revised DISC assembly model that explains how FLIP (L) can have these opposite effects by defining the stoichiometry (with respect to caspase‐8) at which it converts from being anti‐ to pro‐apoptotic at the DISC . We also show that in the complete absence of FLIP (L), procaspase‐8 activation at the TRAIL ‐R2 DISC has significantly slower kinetics, although ultimately the extent of apoptosis is significantly greater. This revised model of DISC assembly also explains why FLIP 's recruitment to the TRAIL ‐R2 DISC is impaired in the absence of caspase‐8 despite showing that it can interact with the DISC adaptor protein FADD and why the short FLIP splice form FLIP (S) is the more potent inhibitor of DISC ‐mediated apoptosis.