Abstract
The coronavirus nucleocapsid protein (N) controls viral genome packaging and contains numerous phosphorylation sites located within unstructured regions. Binding of phosphorylated SARS-CoV N to the host 14-3-3 protein in the cytoplasm was reported to regulate nucleocytoplasmic N shuttling. All seven isoforms of the human 14-3-3 are abundantly present in tissues vulnerable to SARS-CoV-2, where N can constitute up to ~1% of expressed proteins during infection. Although the association between 14-3-3 and SARS-CoV-2 N proteins can represent one of the key host-pathogen interactions, its molecular mechanism and the specific critical phosphosites are unknown. Here, we show that phosphorylated SARS-CoV-2 N protein (pN) dimers, reconstituted via bacterial co-expression with protein kinase A, directly associate, in a phosphorylation-dependent manner, with the dimeric 14-3-3 protein, but not with its monomeric mutant. We demonstrate that pN is recognized by all seven human 14-3-3 isoforms with various efficiencies and deduce the apparent KD to selected isoforms, showing that these are in a low micromolar range. Serial truncations pinpointed a critical phosphorylation site to Ser197, which is conserved among related zoonotic coronaviruses and located within the functionally important, SR-rich region of N. The relatively tight 14-3-3/pN association could regulate nucleocytoplasmic shuttling and other functions of N via occlusion of the SR-rich region, and could also hijack cellular pathways by 14-3-3 sequestration. As such, the assembly may represent a valuable target for therapeutic intervention.
Highlights
The new coronavirus-induced disease, COVID19, has caused a worldwide health crisis with more than 90 million confirmed cases and 1.9 million deaths as of January 2021.1 The pathogen responsible, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is highly similar to the causative agent of the SARS outbreak in 2002–2003 (SARS-CoV) and, to a lesser extent, to the Middle East Respiratory Syndrome Coronavirus (MERS-CoV).[2,3] Each is vastly more pathogenic and deadly than human coronaviruses HCoV-OC43, HCoV-NL63, HCoV-229E, and HCoV-HKU1 which cause seasonal respiratory diseases.[4]
The coronavirus nucleocapsid protein (N) controls viral genome packaging and contains numerous phosphorylation sites located within unstructured regions
All seven isoforms of the human 14-3-3 are abundantly present in tissues vulnerable to SARS-CoV-2, where N can constitute up to ~1% of expressed proteins during infection
Summary
The Mechanism of SARS-CoV-2 Nucleocapsid Protein Recognition by the Human 14-3-3 Proteins. Bayfield 2, De-Sheng Ker 2, Andrey A. 1 - A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia 2 - York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, United Kingdom 3 - Department of Biochemistry, School of Biology, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
