The linear ubiquitin chain assembly complex regulates TRAIL-induced gene activation and cell death |
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Authors: | Elodie Lafont Henning Walczak Elodie Lafont Chahrazade Kantari-Mimoun Peter Draber Diego De Miguel Torsten Hartwig Matthias Reichert Sebastian Kupka Yutaka Shimizu Lucia Taraborrelli Maureen Spit Martin R Sprick Henning Walczak |
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Affiliation: | Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, University College London, London, UK |
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Abstract: | The linear ubiquitin chain assembly complex (LUBAC) is the only known E3 ubiquitin ligase which catalyses the generation of linear ubiquitin linkages de novo. LUBAC is a crucial component of various immune receptor signalling pathways. Here, we show that LUBAC forms part of the TRAIL-R-associated complex I as well as of the cytoplasmic TRAIL-induced complex II. In both of these complexes, HOIP limits caspase-8 activity and, consequently, apoptosis whilst being itself cleaved in a caspase-8-dependent manner. Yet, by limiting the formation of a RIPK1/RIPK3/MLKL-containing complex, LUBAC also restricts TRAIL-induced necroptosis. We identify RIPK1 and caspase-8 as linearly ubiquitinated targets of LUBAC following TRAIL stimulation. Contrary to its role in preventing TRAIL-induced RIPK1-independent apoptosis, HOIP presence, but not its activity, is required for preventing necroptosis. By promoting recruitment of the IKK complex to complex I, LUBAC also promotes TRAIL-induced activation of NF-κB and, consequently, the production of cytokines, downstream of FADD, caspase-8 and cIAP1/2. Hence, LUBAC controls the TRAIL signalling outcome from complex I and II, two platforms which both trigger cell death and gene activation. |
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Keywords: | cell death LUBAC NF-κB TRAIL ubiquitin |
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