title: Highly conserved regions within the spike proteins of human coronaviruses 229E and NL63 determine recognition of their respective cellular receptors.
abstract: We have recently demonstrated that the severe acute respiratory syndrome coronavirus (SARS-CoV) receptor angiotensin converting enzyme 2 (ACE2) also mediates cellular entry of the newly discovered human coronavirus (hCoV) NL63. Here, we show that expression of DC-SIGN augments NL63 spike (S)-protein-driven infection of susceptible cells, while only expression of ACE2 but not DC-SIGN is sufficient for entry into nonpermissive cells, indicating that ACE2 fulfills the criteria of a bona fide hCoV-NL63 receptor. As for SARS-CoV, murine ACE2 is used less efficiently by NL63-S for entry than human ACE2. In contrast, several amino acid exchanges in human ACE2 which diminish SARS-S-driven entry do not interfere with NL63-S-mediated infection, suggesting that SARS-S and NL63-S might engage human ACE2 differentially. Moreover, we observed that NL63-S-driven entry was less dependent on a low-pH environment and activity of endosomal proteases compared to infection mediated by SARS-S, further suggesting differences in hCoV-NL63 and SARS-CoV cellular entry. NL63-S does not exhibit significant homology to SARS-S but is highly related to the S-protein of hCoV-229E, which enters target cells by engaging CD13. Employing mutagenic analyses, we found that the N-terminal unique domain in NL63-S, which is absent in 229E-S, does not confer binding to ACE2. In contrast, the highly homologous C-terminal parts of the NL63-S1 and 229E-S1 subunits in conjunction with distinct amino acids in the central regions of these proteins confer recognition of ACE2 and CD13, respectively. Therefore, despite the high homology of these sequences, they likely form sufficiently distinct surfaces, thus determining receptor specificity.
authors.affiliation: Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Hofmann
authors.forename: Graham
authors.initials: G
authors.lastname: Simmons
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Rennekamp
authors.forename: Chawaree
authors.initials: C
authors.lastname: Chaipan
authors.forename: Thomas
authors.initials: T
authors.lastname: Gramberg
authors.forename: Elke
authors.initials: E
authors.lastname: Heck
authors.forename: Martina
authors.initials: M
authors.lastname: Geier
authors.forename: Anja
authors.initials: A
authors.lastname: Wegele
authors.forename: Andrea
authors.initials: A
authors.lastname: Marzi
authors.forename: Paul
authors.initials: P
authors.lastname: Bates
authors.forename: Stefan
authors.initials: S
authors.lastname: Pöhlmann
mesh_terms: D000085962:Angiotensin-Converting Enzyme 2; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D017934:Coronavirus / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D028941:Coronavirus 229E, Human / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D006224:Cricetinae; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011991:Receptors, Virus / Q000378:metabolism*; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D000085962:Angiotensin-Converting Enzyme 2; D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D007703:Peptidyl-Dipeptidase A; D011956:Receptors, Cell Surface; D011991:Receptors, Virus; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C433029:CLEC4M protein, human; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; C000705307:ACE2 protein, human; C000705328:Ace2 protein, mouse