Myristoylation is required for human immunodeficiency virus type 1 Gag-Gag multimerization in mammalian cells.
The Gag protein of human immunodeficiency virus type 1 directs the virion assembly process. Gag proteins must extensively multimerize during the formation of the spherical immature virion shell. In vitro, virus-like particles can be generated from Gag proteins that lack the N-terminal myristic acid modification or the nucleocapsid (NC) protein. The precise requirements for Gag-Gag multimerization under conditions present in mammalian cells, however, have not been fully elucidated. In this study, a Gag-Gag multimerization assay measuring fluorescence resonance energy transfer was employed to define the Gag domains that are essential for homomultimerization. Three essential components were identified: protein-protein interactions contributed by residues within both the N- and C-terminal domains of capsid (CA), basic residues in NC, and the presence of myristic acid. The requirement of myristic acid for multimerization was reproduced using the heterologous myristoylation sequence from v-src. Only when a leucine zipper dimerization motif was placed in the position of NC was a nonmyristoylated Gag protein able to multimerize. These results support a three-component model for Gag-Gag multimerization that includes membrane interactions mediated by the myristoylated N terminus of Gag, protein-protein interactions between CA domains, and NC-RNA interactions.
Li
Hua
H
Department of Pediatrics, Emory University, Atlanta, GA 30322, USA.
Dou
Jun
J
Ding
Lingmei
L
Spearman
Paul
P
D002460:Cell Line; D031541:Fluorescence Resonance Energy Transfer; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D019814:Myristic Acid / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D019065:Virus Assembly; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000378:metabolism*
D054301:gag Gene Products, Human Immunodeficiency Virus; D019814:Myristic Acid