title: Intermolecular binding between TIFA-FHA and TIFA-pT mediates tumor necrosis factor alpha stimulation and NF-κB activation.
abstract: The forkhead-associated (FHA) domain recognizes phosphothreonine (pT) with high specificity and functional diversity. TIFA (TRAF-interacting protein with 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 and the underlying molecular mechanism remain unclear. Here we identify a novel threonine phosphorylation site on TIFA and show that this phosphorylated threonine (pT) binds with the FHA domain of TIFA, leading to TIFA oligomerization and TIFA-mediated NF-κB activation. Detailed analysis indicated that unphosphorylated TIFA exists as an intrinsic dimer and that the FHA-pT9 binding occurs between different dimers of TIFA. In addition, silencing of endogenous TIFA resulted in attenuation of tumor necrosis factor alpha (TNF-α)-mediated downstream signaling. We therefore propose that the TIFA FHA-pT9 binding provides a previously unidentified link between TNF-α stimulation and NF-κB activation. The intermolecular FHA-pT9 binding between dimers also represents a new mechanism for the FHA domain.
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
authors.forename: Chia-Chi Flora
authors.initials: CC
authors.lastname: Huang
authors.forename: Jui-Hung
authors.initials: JH
authors.lastname: Weng
authors.forename: Tong-You Wade
authors.initials: TY
authors.lastname: Wei
authors.forename: Pei-Yu Gabriel
authors.initials: PY
authors.lastname: Wu
authors.forename: Pang-Hung
authors.initials: PH
authors.lastname: Hsu
authors.forename: Yu-Hou
authors.initials: YH
authors.lastname: Chen
authors.forename: Shun-Chang
authors.initials: SC
authors.lastname: Wang
authors.forename: Dongyan
authors.initials: D
authors.lastname: Qin
authors.forename: Chin-Chun
authors.initials: CC
authors.lastname: Hung
authors.forename: Shui-Tsung
authors.initials: ST
authors.lastname: Chen
authors.forename: Andrew H-J
authors.initials: AH
authors.lastname: Wang
authors.forename: John Y-J
authors.initials: JY
authors.lastname: Shyy
authors.forename: Ming-Daw
authors.initials: MD
authors.lastname: Tsai
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000911:Antibodies, Monoclonal; D051858:Forkhead Transcription Factors / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D010769:Phosphothreonine / Q000737:chemistry; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D051858:Forkhead Transcription Factors; D050505:Mutant Proteins; D016328:NF-kappa B; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C446759:TIFA protein, human; D014409:Tumor Necrosis Factor-alpha; D010769:Phosphothreonine