title: Intact sphingomyelin biosynthetic pathway is essential for intracellular transport of influenza virus glycoproteins.
abstract: Cells genetically deficient in sphingomyelin synthase-1 (SGMS1) or blocked in their synthesis pharmacologically through exposure to a serine palmitoyltransferase inhibitor (myriocin) show strongly reduced surface display of influenza virus glycoproteins hemagglutinin (HA) and neuraminidase (NA). The transport of HA to the cell surface was assessed by accessibility of HA on intact cells to exogenously added trypsin and to HA-specific antibodies. Rates of de novo synthesis of viral proteins in wild-type and SGMS1-deficient cells were equivalent, and HA negotiated the intracellular trafficking pathway through the Golgi normally. We engineered a strain of influenza virus to allow site-specific labeling of HA and NA using sortase. Accessibility of both HA and NA to sortase was blocked in SGMS1-deficient cells and in cells exposed to myriocin, with a corresponding inhibition of the release of virus particles from infected cells. Generation of influenza virus particles thus critically relies on a functional sphingomyelin biosynthetic pathway, required to drive influenza viral glycoproteins into lipid domains of a composition compatible with virus budding and release.
authors.affiliation: Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
authors.forename: Fikadu G
authors.initials: FG
authors.lastname: Tafesse
authors.forename: Sumana
authors.initials: S
authors.lastname: Sanyal
authors.forename: Joseph
authors.initials: J
authors.lastname: Ashour
authors.forename: Carla P
authors.initials: CP
authors.lastname: Guimaraes
authors.forename: Martin
authors.initials: M
authors.lastname: Hermansson
authors.forename: Pentti
authors.initials: P
authors.lastname: Somerharju
authors.forename: Hidde L
authors.initials: HL
authors.lastname: Ploegh
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology; D053898:Biosynthetic Pathways / Q000502:physiology*; D004285:Dogs; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism* / Q000502:physiology; D054884:Host-Pathogen Interactions; D061985:Madin Darby Canine Kidney Cells; D011092:Polyethylene Glycols; D051102:Serine C-Palmitoyltransferase / Q000037:antagonists & inhibitors; D013109:Sphingomyelins / Q000096:biosynthesis*; D017855:Transferases (Other Substituted Phosphate Groups) / Q000172:deficiency; D014357:Trypsin
chemical_list: D005229:Fatty Acids, Monounsaturated; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D013109:Sphingomyelins; C551282:polyethylene glycol monooctylphenyl ether; D011092:Polyethylene Glycols; D051102:Serine C-Palmitoyltransferase; D017855:Transferases (Other Substituted Phosphate Groups); C070186:phosphatidylcholine-ceramide phosphocholine transferase; D014357:Trypsin; C001996:thermozymocidin