title: Efficient and specific rescue of human immunodeficiency virus type 1 budding defects by a Nedd4-like ubiquitin ligase.
abstract: To exit infected cells, human immunodeficiency virus type 1 (HIV-1) exploits the vacuolar protein-sorting pathway by engaging Tsg101 and ALIX through PTAP and LYPx(n)L late assembly (L) domains. In contrast, less-complex retroviruses often use PPxY L domains to recruit Nedd4 family ubiquitin ligases. Although HIV-1 Gag lacks PPxY motifs, we now show that the budding of various HIV-1 L-domain mutants is dramatically enhanced by ectopic Nedd4-2s, a native isoform with a truncated C2 domain. The effect of Nedd4-2s on HIV-1 budding required a catalytically active HECT domain and was specific, since other Nedd4 family proteins showed little activity and an unrelated retrovirus was not rescued. The residual C2 domain of Nedd4-2s was critical for the enhancement of HIV-1 budding and for the association of Nedd4-2s with Gag, as reflected by its incorporation into virus-like particles. Interestingly, the incorporation of Nedd4-2s also depended on its active site, indicating that the ability to form a thioester with ubiquitin was required. These data suggest a novel mechanism by which HIV-1 Gag can connect to cellular budding machinery.
authors.affiliation: Program in Gene Function and Expression, UMass Medical School, Worcester, MA 01605, USA.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Usami
authors.forename: Sergei
authors.initials: S
authors.lastname: Popov
authors.forename: Elena
authors.initials: E
authors.lastname: Popova
authors.forename: Heinrich G
authors.initials: HG
authors.lastname: Göttlinger
mesh_terms: D020816:Amino Acid Motifs; D002460:Cell Line; D056827:Endosomal Sorting Complexes Required for Transport; D015497:HIV-1 / Q000254:growth & development*; D006801:Humans; D000075702:Nedd4 Ubiquitin Protein Ligases; D011485:Protein Binding; D025941:Protein Interaction Mapping; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D025801:Ubiquitin; D054301:gag Gene Products, Human Immunodeficiency Virus; C083002:p6 gag protein, Human immunodeficiency virus 1; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; D044767:Ubiquitin-Protein Ligases