Interactions of SARS Coronavirus Nucleocapsid Protein with the host cell proteasome subunit p42

Qin Wang,Mifang Liang,Jianshi Yu,Quanfu Zhang,Jiandong Li,Dexin Li,Wuxiang Guan,Chuan Li,Tao Wang

doi:10.1186/1743-422x-7-99

Qin Wang, Mifang Liang + Show 7 more

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https://doi.org/10.1186/1743-422x-7-99

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Abstract

BackgroundSevere 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.ResultsUsing 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.ConclusionTo 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.

Highlights

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) spreads rapidly and has a high case-mortality rate
When expression was induced using isopropyl β-D-thiogalactopyranoside (IPTG), cells transfected with pET22bSNP22b produced large amounts of severe acute respiratory syndrome (SARS) nucleocapsid protein (NP), amounting to up to 2% of total soluble protein (Fig. 1A; lanes 4 and 8)
Indirect Enzyme-Linked Immunosorbent Assay (ELISA) data suggested that purified SARS-CoV NP had a specific antibody binding activity similar to the native form

Summary

Introduction

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) spreads rapidly and has a high case-mortality rate. This study sought to discover the host proteins that interact with SARS-CoV NP. The outbreak of severe acute respiratory syndrome (SARS), which began in the Guangdong Province of China, spread rapidly to more than 30 countries during 2003. SARS has an acute onset, is highly transmissible and has a high case-mortality rate (approximately 10%) [1,2]. During SARS infection, three phases of viral replication result in respiratory tract pathological changes and an over-exuberant host immune response. This mediates immunopathological damage of the lungs and other organs, and pulmonary fibrosis. 10% of individuals (6.8% of patients younger and 55% of patients older than 60 years of age) with clinical symptoms died as a consequence of

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