Mechanisms of coronavirus cell entry mediated by the viral spike protein

Viruses. 2012 Jun;4(6):1011-33. doi: 10.3390/v4061011. Epub 2012 Jun 20.

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; fusion; proteolytic activation; spike; viral entry.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Coronavirus / classification
  • Coronavirus / metabolism*
  • Humans
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / metabolism*
  • Receptors, Virus / metabolism
  • Spike Glycoprotein, Coronavirus
  • Viral Envelope Proteins / chemistry
  • Viral Envelope Proteins / metabolism*
  • Viral Fusion Proteins / chemistry
  • Viral Fusion Proteins / metabolism
  • Viral Tropism
  • Virus Internalization*

Substances

  • MHV surface projection glycoprotein
  • Membrane Glycoproteins
  • Receptors, Virus
  • Spike Glycoprotein, Coronavirus
  • Viral Envelope Proteins
  • Viral Fusion Proteins
  • spike glycoprotein, SARS-CoV