A Multibasic Cleavage Site in the Spike Protein of SARS-CoV-2 Is Essential for Infection of Human Lung Cells.
TL;DR: It is reported that the cellular protease furin cleaves the spike protein at the S1/S2 site and that cleavage is essential for S-protein-mediated cell-cell fusion and entry into human lung cells and identifies furin as a potential target for therapeutic intervention.
About: This article is published in Molecular Cell.The article was published on 2020-05-21 and is currently open access. It has received 1443 citations till now. The article focuses on the topics: Furin & Entry into host.
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TL;DR: A review of the literature on mutations of the SARS-CoV-2 spike protein, the primary antigen, focusing on their impacts on antigenicity and contextualizing them in the protein structure is presented in this article.
Abstract: Although most mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome are expected to be either deleterious and swiftly purged or relatively neutral, a small proportion will affect functional properties and may alter infectivity, disease severity or interactions with host immunity. The emergence of SARS-CoV-2 in late 2019 was followed by a period of relative evolutionary stasis lasting about 11 months. Since late 2020, however, SARS-CoV-2 evolution has been characterized by the emergence of sets of mutations, in the context of ‘variants of concern’, that impact virus characteristics, including transmissibility and antigenicity, probably in response to the changing immune profile of the human population. There is emerging evidence of reduced neutralization of some SARS-CoV-2 variants by postvaccination serum; however, a greater understanding of correlates of protection is required to evaluate how this may impact vaccine effectiveness. Nonetheless, manufacturers are preparing platforms for a possible update of vaccine sequences, and it is crucial that surveillance of genetic and antigenic changes in the global virus population is done alongside experiments to elucidate the phenotypic impacts of mutations. In this Review, we summarize the literature on mutations of the SARS-CoV-2 spike protein, the primary antigen, focusing on their impacts on antigenicity and contextualizing them in the protein structure, and discuss them in the context of observed mutation frequencies in global sequence datasets. The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been characterized by the emergence of mutations and so-called variants of concern that impact virus characteristics, including transmissibility and antigenicity. In this Review, members of the COVID-19 Genomics UK (COG-UK) Consortium and colleagues summarize mutations of the SARS-CoV-2 spike protein, focusing on their impacts on antigenicity and contextualizing them in the protein structure, and discuss them in the context of observed mutation frequencies in global sequence datasets.
2,047 citations
TL;DR: Using a variety of statistical and dynamic modeling approaches, the authors estimate that this variant has a 43 to 90% (range of 95% credible intervals, 38 to 130%) higher reproduction number than preexisting variants, and a fitted two-strain dynamic transmission model shows that VOC 202012/01 will lead to large resurgences of COVID-19 cases.
Abstract: A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, VOC 202012/01 (lineage B.1.1.7), emerged in southeast England in September 2020 and is rapidly spreading toward fixation. Using a variety of statistical and dynamic modeling approaches, we estimate that this variant has a 43 to 90% (range of 95% credible intervals, 38 to 130%) higher reproduction number than preexisting variants. A fitted two-strain dynamic transmission model shows that VOC 202012/01 will lead to large resurgences of COVID-19 cases. Without stringent control measures, including limited closure of educational institutions and a greatly accelerated vaccine rollout, COVID-19 hospitalizations and deaths across England in the first 6 months of 2021 were projected to exceed those in 2020. VOC 202012/01 has spread globally and exhibits a similar transmission increase (59 to 74%) in Denmark, Switzerland, and the United States.
1,935 citations
TL;DR: The first discoveries that shape the current understanding of SARS-CoV-2 infection throughout the intracellular viral life cycle are summarized and relate that to the knowledge of coronavirus biology.
Abstract: The SARS-CoV-2 pandemic and its unprecedented global societal and economic disruptive impact has marked the third zoonotic introduction of a highly pathogenic coronavirus into the human population. Although the previous coronavirus SARS-CoV and MERS-CoV epidemics raised awareness of the need for clinically available therapeutic or preventive interventions, to date, no treatments with proven efficacy are available. The development of effective intervention strategies relies on the knowledge of molecular and cellular mechanisms of coronavirus infections, which highlights the significance of studying virus-host interactions at the molecular level to identify targets for antiviral intervention and to elucidate critical viral and host determinants that are decisive for the development of severe disease. In this Review, we summarize the first discoveries that shape our current understanding of SARS-CoV-2 infection throughout the intracellular viral life cycle and relate that to our knowledge of coronavirus biology. The elucidation of similarities and differences between SARS-CoV-2 and other coronaviruses will support future preparedness and strategies to combat coronavirus infections.
1,787 citations
Technische Universität München1, German Center for Neurodegenerative Diseases2, University of Helsinki3, University of Göttingen4, Ludwig Maximilian University of Munich5, Life Sciences Institute6, University of Tartu7, National Institute for Health and Welfare8, University of Queensland9, ETH Zurich10, University of California, Santa Barbara11, Discovery Institute12, University of Zurich13
TL;DR: It is found that neuropilin-1 (NRP1), known to bind furin-cleaved substrates, significantly potentiates SARS-CoV-2 infectivity, an effect blocked by a monoclonal blocking antibody against NRP1.
Abstract: The causative agent of coronavirus disease 2019 (COVID-19) is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For many viruses, tissue tropism is determined by the availability of virus receptors and entry cofactors on the surface of host cells. In this study, we found that neuropilin-1 (NRP1), known to bind furin-cleaved substrates, significantly potentiates SARS-CoV-2 infectivity, an effect blocked by a monoclonal blocking antibody against NRP1. A SARS-CoV-2 mutant with an altered furin cleavage site did not depend on NRP1 for infectivity. Pathological analysis of olfactory epithelium obtained from human COVID-19 autopsies revealed that SARS-CoV-2 infected NRP1-positive cells facing the nasal cavity. Our data provide insight into SARS-CoV-2 cell infectivity and define a potential target for antiviral intervention.
1,304 citations
TL;DR: Hamsters infected with SARS-CoV-2 expressing spike D614G (G614 virus) produced higher infectious titres in nasal washes and the trachea, but not in the lungs, supporting clinical evidence showing that the mutation enhances viral loads in the upper respiratory tract of COVID-19 patients and may increase transmission.
Abstract: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein substitution D614G became dominant during the coronavirus disease 2019 (COVID-19) pandemic1,2. However, the effect of this variant on viral spread and vaccine efficacy remains to be defined. Here we engineered the spike D614G substitution in the USA-WA1/2020 SARS-CoV-2 strain, and found that it enhances viral replication in human lung epithelial cells and primary human airway tissues by increasing the infectivity and stability of virions. Hamsters infected with SARS-CoV-2 expressing spike(D614G) (G614 virus) produced higher infectious titres in nasal washes and the trachea, but not in the lungs, supporting clinical evidence showing that the mutation enhances viral loads in the upper respiratory tract of COVID-19 patients and may increase transmission. Sera from hamsters infected with D614 virus exhibit modestly higher neutralization titres against G614 virus than against D614 virus, suggesting that the mutation is unlikely to reduce the ability of vaccines in clinical trials to protect against COVID-19, and that therapeutic antibodies should be tested against the circulating G614 virus. Together with clinical findings, our work underscores the importance of this variant in viral spread and its implications for vaccine efficacy and antibody therapy.
1,285 citations
References
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TL;DR: Human airway epithelial cells were used to isolate a novel coronavirus, named 2019-nCoV, which formed a clade within the subgenus sarbecovirus, Orthocoronavirinae subfamily, which is the seventh member of the family of coronaviruses that infect humans.
Abstract: In December 2019, a cluster of patients with pneumonia of unknown cause was linked to a seafood wholesale market in Wuhan, China. A previously unknown betacoronavirus was discovered through the use of unbiased sequencing in samples from patients with pneumonia. Human airway epithelial cells were used to isolate a novel coronavirus, named 2019-nCoV, which formed a clade within the subgenus sarbecovirus, Orthocoronavirinae subfamily. Different from both MERS-CoV and SARS-CoV, 2019-nCoV is the seventh member of the family of coronaviruses that infect humans. Enhanced surveillance and further investigation are ongoing. (Funded by the National Key Research and Development Program of China and the National Major Project for Control and Prevention of Infectious Disease in China.).
21,455 citations
TL;DR: Identification and characterization of a new coronavirus (2019-nCoV), which caused an epidemic of acute respiratory syndrome in humans in Wuhan, China, and it is shown that this virus belongs to the species of SARSr-CoV, indicates that the virus is related to a bat coronav virus.
Abstract: Since the outbreak of severe acute respiratory syndrome (SARS) 18 years ago, a large number of SARS-related coronaviruses (SARSr-CoVs) have been discovered in their natural reservoir host, bats1–4. Previous studies have shown that some bat SARSr-CoVs have the potential to infect humans5–7. Here we report the identification and characterization of a new coronavirus (2019-nCoV), which caused an epidemic of acute respiratory syndrome in humans in Wuhan, China. The epidemic, which started on 12 December 2019, had caused 2,794 laboratory-confirmed infections including 80 deaths by 26 January 2020. Full-length genome sequences were obtained from five patients at an early stage of the outbreak. The sequences are almost identical and share 79.6% sequence identity to SARS-CoV. Furthermore, we show that 2019-nCoV is 96% identical at the whole-genome level to a bat coronavirus. Pairwise protein sequence analysis of seven conserved non-structural proteins domains show that this virus belongs to the species of SARSr-CoV. In addition, 2019-nCoV virus isolated from the bronchoalveolar lavage fluid of a critically ill patient could be neutralized by sera from several patients. Notably, we confirmed that 2019-nCoV uses the same cell entry receptor—angiotensin converting enzyme II (ACE2)—as SARS-CoV. Characterization of full-length genome sequences from patients infected with a new coronavirus (2019-nCoV) shows that the sequences are nearly identical and indicates that the virus is related to a bat coronavirus.
16,857 citations
"A Multibasic Cleavage Site in the S..." refers background or methods in this paper
...In particular, we exchanged the multibasic cleavage site against its monobasic counterparts present in SARS-S or RaTG13-S (Figure 2A , RaTG13 is a bat coronavirus closely related to SARS-CoV-2 [Zhou et al., 2020b] )....
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...It is believed that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously termed nCoV-2019) was introduced into the human population from a poorly characterized animal reservoir in late 2019 (Ge et al., 2013; Wang et al., 2020; Zhou et al., 2020b; Zhu et al., 2020) ....
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TL;DR: It is demonstrated that SARS-CoV-2 uses the SARS -CoV receptor ACE2 for entry and the serine protease TMPRSS2 for S protein priming, and it is shown that the sera from convalescent SARS patients cross-neutralized Sars-2-S-driven entry.
15,362 citations
TL;DR: The authors show that this protein binds at least 10 times more tightly than the corresponding spike protein of severe acute respiratory syndrome (SARS)–CoV to their common host cell receptor, and test several published SARS-CoV RBD-specific monoclonal antibodies found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs.
Abstract: The outbreak of a novel coronavirus (2019-nCoV) represents a pandemic threat that has been declared a public health emergency of international concern. The CoV spike (S) glycoprotein is a key target for vaccines, therapeutic antibodies, and diagnostics. To facilitate medical countermeasure development, we determined a 3.5-angstrom-resolution cryo-electron microscopy structure of the 2019-nCoV S trimer in the prefusion conformation. The predominant state of the trimer has one of the three receptor-binding domains (RBDs) rotated up in a receptor-accessible conformation. We also provide biophysical and structural evidence that the 2019-nCoV S protein binds angiotensin-converting enzyme 2 (ACE2) with higher affinity than does severe acute respiratory syndrome (SARS)-CoV S. Additionally, we tested several published SARS-CoV RBD-specific monoclonal antibodies and found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs. The structure of 2019-nCoV S should enable the rapid development and evaluation of medical countermeasures to address the ongoing public health crisis.
7,324 citations
"A Multibasic Cleavage Site in the S..." refers background in this paper
...The S1/S2 site in SARS-CoV-2 forms an exposed loop (Figure 1B) that harbors multiple arginine residues (multibasic) (Walls et al., 2020; Wrapp et al., 2020) that are not found in SARS-CoV-related coronaviruses (SARSr-CoV) but are present in the human coronaviruses OC43, HKU1, and MERS-CoV olecular…...
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...The S1/S2 site in SARS-CoV-2 forms an exposed loop (Figure 1B) that harbors multiple arginine residues (multibasic) (Walls et al., 2020; Wrapp et al., 2020) that are not found in SARS-CoV-related coronaviruses (SARSr-CoV) but are present in the human coronaviruses OC43, HKU1, and MERS-CoV...
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TL;DR: It is demonstrating that cross-neutralizing antibodies targeting conserved S epitopes can be elicited upon vaccination, and it is shown that SARS-CoV-2 S uses ACE2 to enter cells and that the receptor-binding domains of Sars- coV- 2 S and SARS S bind with similar affinities to human ACE2, correlating with the efficient spread of SATS among humans.
7,219 citations
"A Multibasic Cleavage Site in the S..." refers background or result in this paper
...SARS-2-S WT (wild type) was efficiently cleaved at the S1/S2 site (Figure 2B), in keeping with published data (Hoffmann et al., 2020; Walls et al., 2020)....
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...The S1/S2 site in SARS-CoV-2 forms an exposed loop (Figure 1B) that harbors multiple arginine residues (multibasic) (Walls et al., 2020; Wrapp et al., 2020) that are not found in SARS-CoV-related coronaviruses (SARSr-CoV) but are present in the human coronaviruses OC43, HKU1, and MERS-CoV...
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...In contrast, entry into TMPRSS2 Vero cells, which is known to be cathepsin B/L dependent, was not affected by these mutations (Figure 1E), in keeping with results reported by Walls and colleagues (Walls et al., 2020)....
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