title: The functional interactome of PYHIN immune regulators reveals IFIX is a sensor of viral DNA.
abstract: The human PYHIN proteins, AIM2, IFI16, IFIX, and MNDA, are critical regulators of immune response, transcription, apoptosis, and cell cycle. However, their protein interactions and underlying mechanisms remain largely uncharacterized. Here, we provide the interaction network for all PYHIN proteins and define a function in sensing of viral DNA for the previously uncharacterized IFIX protein. By designing a cell-based inducible system and integrating microscopy, immunoaffinity capture, quantitative mass spectrometry, and bioinformatics, we identify over 300 PYHIN interactions reflective of diverse functions, including DNA damage response, transcription regulation, intracellular signaling, and antiviral response. In view of the IFIX interaction with antiviral factors, including nuclear PML bodies, we further characterize IFIX and demonstrate its function in restricting herpesvirus replication. We discover that IFIX detects viral DNA in both the nucleus and cytoplasm, binding foreign DNA via its HIN domain in a sequence-non-specific manner. Furthermore, IFIX contributes to the induction of interferon response. Our results highlight the value of integrative proteomics in deducing protein function and establish IFIX as an antiviral DNA sensor important for mounting immune responses.
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: Benjamin A
authors: BA
authors: Diner
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: Tuo
authors: T
authors: Li
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: Todd M
authors: TM
authors: Greco
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: Marni S
authors: MS
authors: Crow
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: John A
authors: JA
authors: Fuesler
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA.
authors: Jennifer
authors: J
authors: Wang
authors: Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA icristea@princeton.edu.
authors: Ileana M
authors: IM
authors: Cristea
mesh_terms: D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D030541:Databases, Genetic; D057809:HEK293 Cells; D018259:Herpesvirus 1, Human / Q000302:isolation & purification; D006801:Humans; D007155:Immunologic Factors / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C410167:AIM2 protein, human; D015214:Antigens, Differentiation, Myelomonocytic; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D007155:Immunologic Factors; C075373:MNDA protein, human; D009687:Nuclear Proteins; C487565:PYHIN1 protein, human; D010750:Phosphoproteins; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D014157:Transcription Factors; C076700:IFI16 protein, human
keywords: DNA sensing; IFIX; PYHIN; innate immunity; interactome