title: Interactions of SARS coronavirus nucleocapsid protein with the host cell proteasome subunit p42.
abstract: BACKGROUND
  Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) spreads rapidly and has a high case-mortality rate. The nucleocapsid protein (NP) of SARS-CoV may be critical for pathogenicity. This study sought to discover the host proteins that interact with SARS-CoV NP.
  
  
  RESULTS
  Using surface plasmon resonance biomolecular interaction analysis (SPR/BIA) and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry, we found that only the proteasome subunit p42 from human fetal lung diploid fibroblast (2BS) cells bound to SARS-CoV NP. This interaction was confirmed by the glutathione S-transferase (GST) fusion protein pulldown technique. The co-localization signal of SARS-CoV NP and proteasome subunit p42 in 2BS cells was detected using indirect immunofluorescence and confocal microscopy. p42 is a subunit of the 26S proteasome; this large, multi-protein complex is a component of the ubiquitin-proteasome pathway, which is involved in a variety of basic cellular processes and inflammatory responses.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report that SARS-CoV NP interacts with the proteasome subunit p42 within host cells. These data enhance our understanding of the molecular mechanisms of SARS-CoV pathogenicity and the means by which SARS-CoV interacts with host cells.
authors.affiliation: State Key Laboratory for Molecular Virology and Genetic Engineering, National Institute for Viral Disease Control and Prevention, China CDC 100 Ying Xin Jie, Xuan Wu Qu, Beijing 100052, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Chuan
authors.initials: C
authors.lastname: Li
authors.forename: Quanfu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Jiandong
authors.initials: J
authors.lastname: Li
authors.forename: Wuxiang
authors.initials: W
authors.lastname: Guan
authors.forename: Jianshi
authors.initials: J
authors.lastname: Yu
authors.forename: Mifang
authors.initials: M
authors.lastname: Liang
authors.forename: Dexin
authors.initials: D
authors.lastname: Li
mesh_terms: D002460:Cell Line; D000086462:Coronavirus Nucleocapsid Proteins; D054884:Host-Pathogen Interactions; D006801:Humans; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000378:metabolism*; D045169:Severe Acute Respiratory Syndrome / Q000235:genetics / Q000378:metabolism* / Q000821:virology
chemical_list: D000086462:Coronavirus Nucleocapsid Proteins; D019590:Nucleocapsid Proteins; D046988:Proteasome Endopeptidase Complex