title: Palmitoylation of SARS-CoV S protein is necessary for partitioning into detergent-resistant membranes and cell-cell fusion but not interaction with M protein.
abstract: Coronaviruses are enveloped RNA viruses that generally cause mild disease in humans. However, the recently emerged coronavirus that caused severe acute respiratory syndrome (SARS-CoV) is the most pathogenic human coronavirus discovered to date. The SARS-CoV spike (S) protein mediates virus entry by binding cellular receptors and inducing fusion between the viral envelope and the host cell membrane. Coronavirus S proteins are palmitoylated, which may affect function. Here, we created a non-palmitoylated SARS-CoV S protein by mutating all nine cytoplasmic cysteine residues. Palmitoylation of SARS-CoV S was required for partitioning into detergent-resistant membranes and for cell-cell fusion. Surprisingly, however, palmitoylation of S was not required for interaction with SARS-CoV M protein. This contrasts with the requirement for palmitoylation of mouse hepatitis virus S protein for interaction with M protein and may point to important differences in assembly and infectivity of these two coronaviruses.
authors.affiliation: Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Corrin E
authors.initials: CE
authors.lastname: McBride
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Machamer
mesh_terms: D000818:Animals; D002459:Cell Fusion; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology*; D002522:Chlorocebus aethiops; D000086862:Coronavirus M Proteins; D003902:Detergents; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D006801:Humans; D054878:Lipoylation; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000378:metabolism*; D064370:Spike Glycoprotein, Coronavirus; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000086862:Coronavirus M Proteins; D003902:Detergents; C000706237:M protein, SARS-CoV; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus