Interactions of SARS coronavirus nucleocapsid protein with the host cell proteasome subunit p42.
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.
Wang
Qin
Q
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.
Li
Chuan
C
Zhang
Quanfu
Q
Wang
Tao
T
Li
Jiandong
J
Guan
Wuxiang
W
Yu
Jianshi
J
Liang
Mifang
M
Li
Dexin
D
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
D000086462:Coronavirus Nucleocapsid Proteins; D019590:Nucleocapsid Proteins; D046988:Proteasome Endopeptidase Complex