Binding and Enhanced Binding between Key Immunity Proteins TRAF6 and TIFA

• Published in: Chembiochem : a European journal of chemical biology Vol. 20; no. 2; pp. 140 - 146
• Main Authors: Huang, Wei‐Cheng, Liao, Jiahn‐Haur, Hsiao, Tzu‐Chun, Wei, Tong‐You Wade, Maestre‐Reyna, Manuel, Bessho, Yoshitaka, Tsai, Ming‐Daw
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 18-01-2019
• Subjects: Activation; Adaptor Proteins, Signal Transducing - chemistry; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Binding; Binding Sites; biological activity; Forkhead protein; HEK293 Cells; Heptose; Humans; Immunity; Innate immunity; Intracellular Signaling Peptides and Proteins; Lipopolysaccharides; mutagenesis; noncovalent interactions; Peptides; Protein Conformation; Proteins; protein–protein interactions; Residues; structure elucidation; TNF Receptor-Associated Factor 6 - chemistry; TNF Receptor-Associated Factor 6 - genetics; TNF Receptor-Associated Factor 6 - metabolism; TRAF6 protein; biological activity; structure elucidation; noncovalent interactions; mutagenesis; protein-protein interactions
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.201800436

Human tumor necrosis factor receptor associated factor (TRAF)‐interacting protein, with a forkhead‐associated domain (TIFA), is a key regulator of NF‐κB activation. It also plays a key role in the activation of innate immunity in response to bacterial infection, through heptose 1,7‐bisphosphate (HBP); a metabolite of lipopolysaccharide (LPS). However, the mechanism of TIFA function is largely unexplored, except for the suggestion of interaction with TRAF6. Herein, we provide evidence for direct binding, albeit weak, between TIFA and the TRAF domain of TRAF6, and it is shown that the binding is enhanced for a rationally designed double mutant, TIFA S174Q/M179D. Enhanced binding was also demonstrated for endogenous full‐length TRAF6. Furthermore, the structures of the TRAF domain complexes with the consensus TRAF‐binding peptides from the C terminus of wild‐type and S174Q/M179D mutant TIFA, showing salt‐bridge formation between residues 177–181 of TIFA and the binding pocket residues of the TRAF domain, were solved. Taken together, the results provide direct evidence and a structural basis for the TIFA–TRAF6 interaction, and show how this important biological function can be modulated.
Bridging the gap: Human tumor necrosis factor receptor associated factor (TRAF)‐interacting protein, with a forkhead‐associated domain (TIFA), is a key regulator of NF‐κB activation and plays a key role in activating the immune response to bacterial infection. An important signal transduction protein–protein complex of human TIFA and TRAF6 provides direct evidence and a structural basis for their interaction.