title: The association of Nef with a cellular serine/threonine kinase and its enhancement of infectivity are viral isolate dependent.
abstract: The nef genes of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) encode a 27- to 34-kDa myristoylated protein which induces downregulation of CD4 surface levels and enhances virus infectivity. In adult macaques, Nef has been implicated in pathogenesis and disease progression. Both HIV-1 SF2 Nef and SIVmac239 Nef have been shown to associate with a cellular serine/threonine kinase. We tested five functional Nef isolates to examine whether this kinase association is a property conserved among different isolates. HIV-1 SF2 and 248 and SIVmac239 Nef proteins were found associated with the kinase. HIV-1 NL4-3 and 233 Nef proteins were found weakly associated or not associated with the kinase. All five Nef isolates efficiently downregulated CD4 cell surface expression, suggesting that the association with this cellular kinase is not required for Nef to downregulate CD4. Comparison of the SF2 and NL4-3 isolates shows a differential ability of Nef to enhance infectivity that suggests a possible correlation between kinase association and enhancement of infectivity.
authors.affiliation: Department of Virology and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38101, USA.
authors.forename: T
authors.initials: T
authors.lastname: Luo
authors.forename: J V
authors.initials: JV
authors.lastname: Garcia
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000096:biosynthesis; D002460:Cell Line; D015536:Down-Regulation; D015693:Gene Products, nef / Q000302:isolation & purification / Q000378:metabolism*; D015754:Genes, nef; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D006801:Humans; D008251:Macaca; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification / Q000378:metabolism*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000503:physiopathology; D015302:Simian Immunodeficiency Virus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D013045:Species Specificity; D013601:T-Lymphocytes; D054311:nef Gene Products, Human Immunodeficiency Virus
chemical_list: D015704:CD4 Antigens; D015693:Gene Products, nef; D054311:nef Gene Products, Human Immunodeficiency Virus; D017346:Protein Serine-Threonine Kinases