The interaction between RIPK1 and FADD controls perinatal lethality and inflammation
Diego A. Rodríguez, Bart Tummers, Jeremy J.P. Shaw, Giovanni Quarato, Ricardo Weinlich, James G. Cripps, Patrick Fitzgerald, Laura J. Janke, S. William Pelletier, Jeremy Chase Crawford, Douglas R. Green
Abstract
Perturbation of the apoptosis and necroptosis pathways critically influences embryogenesis. Receptor-associated protein kinase-1 (RIPK1) interacts with Fas-associated via death domain (FADD)-caspase-8-cellular Flice-like inhibitory protein long (cFLIP L ) to regulate both extrinsic apoptosis and necroptosis. Here, we describe Ripk1 -mutant animals ( Ripk1 R588E [RE]) in which the interaction between FADD and RIPK1 is disrupted, leading to embryonic lethality. This lethality is not prevented by further removal of the kinase activity of Ripk1 ( Ripk1 R588E K45A [REKA]). Both Ripk1 RE and Ripk1 REKA animals survive to adulthood upon ablation of Ripk3 . While embryonic lethality of Ripk1 RE mice is prevented by ablation of the necroptosis effector mixed lineage kinase-like (MLKL), animals succumb to inflammation after birth. In contrast, Mlkl ablation does not prevent the death of Ripk1 REKA embryos, but animals reach adulthood when both MLKL and caspase-8 are removed. Ablation of the nucleic acid sensor Zbp1 largely prevents lethality in both Ripk1 RE and Ripk1 REKA embryos. Thus, the RIPK1-FADD interaction prevents Z-DNA binding protein-1 (ZBP1)-induced, RIPK3-caspase-8-mediated embryonic lethality, affected by the kinase activity of RIPK1.