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Cytoplasmic Tail Truncation Stabilizes S1-S2 Association and Enhances S Protein Incorporation into SARS-CoV-2 Pseudovirions.
Zhang, Lizhou; Hom, Nancy; Ojha, Amrita; Lovendahl, Klaus N; Mou, Huihui; Lee, Kelly K; Choe, Hyeryun.
Afiliação
  • Zhang L; Department of Immunology and Microbiology, Scripps Biomedical Research at the University of Florida, Jupiter, Florida, USA.
  • Hom N; Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
  • Ojha A; Department of Immunology and Microbiology, Scripps Biomedical Research at the University of Florida, Jupiter, Florida, USA.
  • Lovendahl KN; Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
  • Mou H; Department of Immunology and Microbiology, Scripps Biomedical Research at the University of Florida, Jupiter, Florida, USA.
  • Lee KK; Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA.
  • Choe H; Department of Immunology and Microbiology, Scripps Biomedical Research at the University of Florida, Jupiter, Florida, USA.
J Virol ; 97(3): e0165022, 2023 03 30.
Article em En | MEDLINE | ID: mdl-36790205
ABSTRACT
Truncations of the cytoplasmic tail (CT) of entry proteins of enveloped viruses dramatically increase the infectivity of pseudoviruses (PVs) bearing these proteins. Several mechanisms have been proposed to explain this enhanced entry, including an increase in cell surface expression. However, alternative explanations have also been forwarded, and the underlying mechanisms for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S protein remain undetermined. Here, we show that the partial or complete deletion of the CT (residues 19 to 35) does not modify SARS-CoV-2 S protein expression on the cell surface when the S2 subunit is measured, whereas it is significantly increased when the S1 subunit is measured. We also show that the higher level of S1 in these CT-truncated S proteins reflects the decreased dissociation of the S1 subunit from the S2 subunit. In addition, we demonstrate that CT truncation further promotes S protein incorporation into PV particles, as indicated by biochemical analyses and cryo-electron microscopy. Thus, our data show that two distinct mechanisms contribute to the markedly increased infectivity of PVs carrying CT-truncated SARS-CoV-2 S proteins and help clarify the interpretation of the results of studies employing such PVs. IMPORTANCE Various forms of PVs have been used as tools to evaluate vaccine efficacy and study virus entry steps. When PV infectivity is inherently low, such as that of SARS-CoV-2, a CT-truncated version of the viral entry glycoprotein is widely used to enhance PV infectivity, but the mechanism underlying this enhanced PV infectivity has been unclear. Here, our study identified two mechanisms by which the CT truncation of the SARS-CoV-2 S protein dramatically increases PV infectivity a reduction of S1 shedding and an increase in S protein incorporation into PV particles. An understanding of these mechanisms can clarify the mechanistic bases for the differences observed among various assays employing such PVs.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Vírion / Glicoproteína da Espícula de Coronavírus / SARS-CoV-2 Tipo de estudo: Risk_factors_studies Limite: Humans Idioma: En Ano de publicação: 2023 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Vírion / Glicoproteína da Espícula de Coronavírus / SARS-CoV-2 Tipo de estudo: Risk_factors_studies Limite: Humans Idioma: En Ano de publicação: 2023 Tipo de documento: Article