title: Respiratory syncytial virus NS1 protein colocalizes with mitochondrial antiviral signaling protein MAVS following infection.
abstract: Respiratory syncytial virus (RSV) nonstructural protein 1(NS1) attenuates type-I interferon (IFN) production during RSV infection; however the precise role of RSV NS1 protein in orchestrating the early host-virus interaction during infection is poorly understood. Since NS1 constitutes the first RSV gene transcribed and the production of IFN depends upon RLR (RIG-I-like receptor) signaling, we reasoned that NS1 may interfere with this signaling. Herein, we report that NS1 is localized to mitochondria and binds to mitochondrial antiviral signaling protein (MAVS). Live-cell imaging of rgRSV-infected A549 human epithelial cells showed that RSV replication and transcription occurs in proximity to mitochondria. NS1 localization to mitochondria was directly visualized by confocal microscopy using a cell-permeable chemical probe for His(6)-NS1. Further, NS1 colocalization with MAVS in A549 cells infected with RSV was shown by confocal laser microscopy and immuno-electron microscopy. NS1 protein is present in the mitochondrial fraction and co-immunoprecipitates with MAVS in total cell lysatesof A549 cells transfected with the plasmid pNS1-Flag. By immunoprecipitation with anti-RIG-I antibody, RSV NS1 was shown to associate with MAVS at an early stage of RSV infection, and to disrupt MAVS interaction with RIG-I (retinoic acid inducible gene) and the downstream IFN antiviral and inflammatory response. Together, these results demonstrate that NS1 binds to MAVS and that this binding inhibits the MAVS-RIG-I interaction required for IFN production.
authors.affiliation: James A Haley Veteran's Administration Hospital, Tampa, Florida, United States of America.
authors.forename: Sandhya
authors.initials: S
authors.lastname: Boyapalle
authors.forename: Terianne
authors.initials: T
authors.lastname: Wong
authors.forename: Julio
authors.initials: J
authors.lastname: Garay
authors.forename: Michael
authors.initials: M
authors.lastname: Teng
authors.forename: Homero
authors.initials: H
authors.lastname: San Juan-Vergara
authors.forename: Subhra
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Shyam
authors.initials: S
authors.lastname: Mohapatra
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation; D016898:Interferon-alpha / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D018357:Respiratory Syncytial Virus Infections / Q000378:metabolism* / Q000821:virology*; D012136:Respiratory Syncytial Viruses / Q000378:metabolism*; D015398:Signal Transduction; D017361:Viral Nonstructural Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016898:Interferon-alpha; C505371:MAVS protein, human; C437968:PLAAT4 protein, human; D018168:Receptors, Retinoic Acid; D017361:Viral Nonstructural Proteins; D016899:Interferon-beta