Intermolecular Binding between TIFA-FHA and TIFA-pT Mediates Tumor Necrosis Factor Alpha Stimulation and NF-κB Activation

• DOI: 10.1128/mcb.00438-12
• Publication Date: 2012-05-08T07:00:17Z
• Authors: Chia-Chi Flora Huang; Jui-Hung Weng; Tong-You Wade Wei; Pei-Yu Gabriel Wu; Pang-Hung Hsu; Yu-Hou Chen; Shun-Chang Wang; Dongyan Qin; Chin-Chun Hung; Shui-Tsung Chen; Andrew H.-J. Wang; John Y.-J. Shyy; Ming-Daw Tsai
• Keywords: 570; 0303 health sciences; Sequence Homology, Amino Acid; Tumor Necrosis Factor-alpha; Molecular Sequence Data; NF-kappa B; 610; Antibodies, Monoclonal; Forkhead Transcription Factors; Models, Biological; Recombinant Proteins; 03 medical and health sciences; HEK293 Cells; Phosphothreonine; Amino Acid Substitution; Humans; Mutant Proteins; Protein Interaction Domains and Motifs; RNA Interference; Amino Acid Sequence; Protein Multimerization; RNA, Small Interfering; Adaptor Proteins, Signal Transducing; Signal Transduction

The forkhead-associated (FHA) domain recognizes phosphothreonine (pT) with high specificity and functional diversity. TIFA (TRAF-interacting protein an FHA domain) is the smallest FHA-containing human protein. Its overexpression was previously suggested to provoke NF-κB activation, yet its exact roles in this signaling pathway underlying molecular mechanism remain unclear. Here we identify a novel threonine phosphorylation site on show that phosphorylated binds of TIFA, leading oligomerization TIFA-mediated activation. Detailed analysis indicated unphosphorylated exists as intrinsic dimer FHA-pT9 binding occurs between different dimers TIFA. In addition, silencing endogenous resulted attenuation tumor necrosis factor alpha (TNF-α)-mediated downstream signaling. We therefore propose provides unidentified link TNF-α stimulation intermolecular also represents new for domain.