Apoptbsis plays critical roles in mammalian biology including embryonic development, cellular homeostasis and immune regulation. Genetic mutations or abnormal expression of apoptosis pathway proteins are associated with many human diseases. Apoptosis is initiated via assembly of multimeric caspase-activating signaling complexes. In the extrinsic cell death pathway, death receptors (members of the tumor necrosis factor (TNF) receptor superfamily) such as Fas (also known as CD95 or APO-1) assemble into an oligomeric death inducing signaling complex (DISC) upon ligand stimulation. Similarly, in the caspase-2 activation pathway, the p53-inducible protein PIDD assembles into an oligomeric complex known as the PIDDosome. Death domain (DD) and death effector domains (DED) play important roles in both DISC and PIDDosome formation. For DISC assembly, the intracellular DD of Fas interacts with the C-terminal DD of the adapter protein FADD and the N-terminal DED of FADD interacts with the tandem DED in caspase-8 (or caspase-10) to form the ternary complex of Fas, FADD and caspase-8. In addition to caspase-8 and -10, cellular and viral FLIPs (cFLIPs and vFLIPs) are also tandem DED-containing proteins that interact with FADD DED and inhibit the function of the DISC. For PIDDosome assembly, one important interaction is between the DD of PIDD and the DD of the adapter protein RAIDD. Caspase recruitment into these complexes initiates proteolytic auto-processing and caspase activation. In this application, we propose to use a combination of biochemical and cell biological approaches study the molecular mechanisms that govern the assembly of these complexes.
The specific aims are: 1) to reconstitute these apoptotic signaling complexes in vitro and to characterize them in cellular systems; 2) to elucidate the molecular basis of the Fas DD:FADD DD interaction; 3) to elucidate the molecular basis of the PIDD DD:RAIDD DD interaction; 4) to elucidate the interaction of FADD DED with tandem DEDs.

Public Health Relevance

Engagement of the TLR/IL-1R pathway in appropriate physiological contexts initiates the development of protective immune responses. However, the complexity of this pathway also renders itself susceptible to interruption and dysregulation, leading to its association with many human diseases. For example, inherited mutations or polymorphisms in TIR-adapters and IRAKs may cause either extreme sensitivity to or protection against infections. Other types of dysregulation in the pathway contribute to both diseases in the immune system such as inflammatory disorders, autoimmune diseases and allergy, and diseases beyond the immune system such as cancer, insulin resistance, atherosclerosis, and painful neuropathy.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Method to Extend Research in Time (MERIT) Award (R37)
Project #
Application #
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Singleton, Kentner L
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Children's Hospital Boston
United States
Zip Code
Feltham, Rebecca; Jamal, Kunzah; Tenev, Tencho et al. (2018) Mind Bomb Regulates Cell Death during TNF Signaling by Suppressing RIPK1's Cytotoxic Potential. Cell Rep 23:470-484
Fu, Tian-Min; Shen, Chen; Li, Qiubai et al. (2018) Mechanism of ubiquitin transfer promoted by TRAF6. Proc Natl Acad Sci U S A 115:1783-1788
Hauenstein, Arthur V; Xu, Guozhou; Kabaleeswaran, Venkataraman et al. (2017) Evidence for M1-Linked Polyubiquitin-Mediated Conformational Change in NEMO. J Mol Biol 429:3793-3800
Wang, Li; Qiao, Qi; Ferrao, Ryan et al. (2017) Crystal structure of human IRAK1. Proc Natl Acad Sci U S A 114:13507-13512
Kleino, Anni; Ramia, Nancy F; Bozkurt, Gunes et al. (2017) Peptidoglycan-Sensing Receptors Trigger the Formation of Functional Amyloids of the Adaptor Protein Imd to Initiate Drosophila NF-?B Signaling. Immunity 47:635-647.e6
Fu, Tian-Min; Li, Yang; Lu, Alvin et al. (2016) Cryo-EM Structure of Caspase-8 Tandem DED Filament Reveals Assembly and Regulation Mechanisms of the Death-Inducing Signaling Complex. Mol Cell 64:236-250
Fu, Qingshan; Fu, Tian-Min; Cruz, Anthony C et al. (2016) Structural Basis and Functional Role of Intramembrane Trimerization of the Fas/CD95 Death Receptor. Mol Cell 61:602-613
Hauenstein, Arthur V; Zhang, Liman; Wu, Hao (2015) The hierarchical structural architecture of inflammasomes, supramolecular inflammatory machines. Curr Opin Struct Biol 31:75-83
Yin, Qian; Fu, Tian-Min; Li, Jixi et al. (2015) Structural biology of innate immunity. Annu Rev Immunol 33:393-416
Wei, Shuo; Kozono, Shingo; Kats, Lev et al. (2015) Active Pin1 is a key target of all-trans retinoic acid in acute promyelocytic leukemia and breast cancer. Nat Med 21:457-66

Showing the most recent 10 out of 22 publications