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Mechanisms of Coronavirus Cell Entry Mediated by the Viral Spike Protein
Center for Infection and Immunity of Lille, CNRS UMR8204, INSERM U1019, Institut Pasteur de Lille, Université Lille Nord de France, 59000 Lille, France
Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853, USA
* Author to whom correspondence should be addressed.
Received: 8 May 2012; in revised form: 13 June 2012 / Accepted: 14 June 2012 / Published: 20 June 2012
Abstract: Coronaviruses are enveloped positive-stranded RNA viruses that replicate in the cytoplasm. To deliver their nucleocapsid into the host cell, they rely on the fusion of their envelope with the host cell membrane. The spike glycoprotein (S) mediates virus entry and is a primary determinant of cell tropism and pathogenesis. It is classified as a class I fusion protein, and is responsible for binding to the receptor on the host cell as well as mediating the fusion of host and viral membranes—A process driven by major conformational changes of the S protein. This review discusses coronavirus entry mechanisms focusing on the different triggers used by coronaviruses to initiate the conformational change of the S protein: receptor binding, low pH exposure and proteolytic activation. We also highlight commonalities between coronavirus S proteins and other class I viral fusion proteins, as well as distinctive features that confer distinct tropism, pathogenicity and host interspecies transmission characteristics to coronaviruses.
Keywords: coronavirus; spike; viral entry; fusion; proteolytic activation
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Belouzard, S.; Millet, J.K.; Licitra, B.N.; Whittaker, G.R. Mechanisms of Coronavirus Cell Entry Mediated by the Viral Spike Protein. Viruses 2012, 4, 1011-1033.
Belouzard S, Millet JK, Licitra BN, Whittaker GR. Mechanisms of Coronavirus Cell Entry Mediated by the Viral Spike Protein. Viruses. 2012; 4(6):1011-1033.
Belouzard, Sandrine; Millet, Jean K.; Licitra, Beth N.; Whittaker, Gary R. 2012. "Mechanisms of Coronavirus Cell Entry Mediated by the Viral Spike Protein." Viruses 4, no. 6: 1011-1033.