title: Two palmitylated cysteine residues of the severe acute respiratory syndrome coronavirus spike (S) protein are critical for S incorporation into virus-like particles, but not for M-S co-localization.
abstract: The endodomain of several coronavirus (CoV) spike (S) proteins contains palmitylated cysteine residues and enables co-localization and interaction with the CoV membrane (M) protein. Depalmitylation of mouse hepatitis virus S proteins abolished this interaction, resulting in the failure of S incorporation into virions. In contrast, an immunofluorescence assay (IFA) showed that depalmitylated severe acute respiratory syndrome coronavirus (SCoV) S proteins still co-localized with the M protein in the budding site. Here, we determined the ability of depalmitylated SCoV S mutants to incorporate S into virus-like particles (VLPs). IFA confirmed that all SCoV S mutants co-localized with the M protein intracellularly. However, the mutants lacking two cysteine residues (C(1234/1235)) failed to incorporate S into VLPs. This indicated that these palmitylated cysteines are essential for S incorporation, but are not involved in S co-localization mediated by the M protein. Our findings suggest that M-S co-localization and S incorporation occur independently of one another in SCoV virion assembly.
authors.affiliation: Laboratory of Virology and Viral Infections, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ujike
authors.affiliation: Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1019, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Huang
authors.affiliation: Department of Virology III, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Shirato
authors.affiliation: Department of Virology III, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.
authors.forename: Shutoku
authors.initials: S
authors.lastname: Matsuyama
authors.affiliation: Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1019, USA.
authors.forename: Shinji
authors.initials: S
authors.lastname: Makino
authors.affiliation: Laboratory of Virology and Viral Infections, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan.
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Taguchi
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D000086862:Coronavirus M Proteins; D003545:Cysteine / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D019308:Palmitic Acid / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000378:metabolism* / Q000502:physiology; D045169:Severe Acute Respiratory Syndrome / Q000821:virology*; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014771:Virion / Q000378:metabolism / Q000502:physiology; D019065:Virus Assembly / Q000502:physiology
chemical_list: D000086862:Coronavirus M Proteins; 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; D019308:Palmitic Acid; D003545:Cysteine