title: Association of dengue virus NS1 protein with lipid rafts.
abstract: During the replication of dengue virus, a viral non-structural glycoprotein, NS1, associates with the membrane on the cell surface and in the RNA replication complex. NS1 lacks a transmembrane domain, and the mechanism by which it associates with the membrane remains unclear. This study aimed to investigate whether membrane-bound NS1 is present in lipid rafts in dengue virus-infected cells. Double immunofluorescence staining of infected HEK-293T cells revealed that NS1 localized with raft-associated molecules, ganglioside GM1 and CD55, on the cell surface. In a flotation gradient centrifugation assay, a small proportion of NS1 in Triton X-100 cell lysate consistently co-fractionated with raft markers. Association of NS1 with lipid rafts was detected for all four dengue serotypes, as well as for Japanese encephalitis virus. Analysis of recombinant NS1 forms showed that glycosylated NS1 dimers stably expressed in HEK-293T cells without an additional C-terminal sequence, or with a heterologous transmembrane domain, failed to associate with lipid rafts. In contrast, glycosylphosphatidylinositol-linked recombinant NS1 exhibited a predilection for lipid rafts. These results indicate an association of a minor subpopulation of NS1 with lipid rafts during dengue virus infection and suggest that modification of NS1, possibly lipidation, is required for raft association.
authors.affiliation: Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.|Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand.
authors.forename: Sansanee
authors.initials: S
authors.lastname: Noisakran
authors.affiliation: Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Thanyaporn
authors.initials: T
authors.lastname: Dechtawewat
authors.affiliation: Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
authors.forename: Panisadee
authors.initials: P
authors.lastname: Avirutnan
authors.affiliation: Department of Immunoregulation, Research Institute of Microbial Diseases, Osaka University, Osaka, Japan.
authors.forename: Taroh
authors.initials: T
authors.lastname: Kinoshita
authors.affiliation: Thailand-Japan Research Collaboration Center on Emerging and Re-Emerging Infections (RCC-ERI), Nonthaburi 11000, Thailand.
authors.forename: Uamporn
authors.initials: U
authors.lastname: Siripanyaphinyo
authors.affiliation: Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.|Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand.
authors.forename: Chunya
authors.initials: C
authors.lastname: Puttikhunt
authors.affiliation: Department of Clinical Immunology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.|Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand.
authors.forename: Watchara
authors.initials: W
authors.lastname: Kasinrerk
authors.affiliation: Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.|Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand.
authors.forename: Prida
authors.initials: P
authors.lastname: Malasit
authors.affiliation: Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.|Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand.
authors.forename: Nopporn
authors.initials: N
authors.lastname: Sittisombut
mesh_terms: D000818:Animals; D018958:CD55 Antigens / Q000378:metabolism*; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D003716:Dengue Virus / Q000145:classification / Q000378:metabolism / Q000472:pathogenicity*; D004847:Epithelial Cells / Q000378:metabolism / Q000821:virology*; D005455:Fluorescent Antibody Technique; D005677:G(M1) Ganglioside / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000378:metabolism*
chemical_list: D018958:CD55 Antigens; C100315:NS1 protein, Flavivirus; D017361:Viral Nonstructural Proteins; D005677:G(M1) Ganglioside