Subcellular localization of the Vif protein of human immunodeficiency virus type 1.
The Vif (viral infectivity factor) protein of human immunodeficiency virus type 1 (HIV-1) has been shown to dramatically enhance the infectivity of HIV-1 virus particles during virus production. The subcellular localization of Vif was examined to elucidate cellular pathways which may be important for Vif function. Indirect immunofluorescence staining of Vif demonstrated a diffuse cytoplasmic distribution and showed that most Vif was not associated with the Golgi complex, a proposed site of localization (B. Guy, M. Geist, K. Dott, D. Spehner, M.-P. Kieny, and J.-P. Lecocq, J. Virol. 65:1325-1331, 1991). Subcellular fractionation of transfected COS cells and HIV-1-infected Jurkat and CEM cells demonstrated that Vif is a cytoplasmic protein which exists in both a soluble cytosolic form and membrane-associated form. The membrane-associated form of Vif is a peripheral membrane protein which is tightly associated with the cytoplasmic side of cellular membranes. The C terminus of Vif was required for the stable association of Vif with membranes. The C terminus was also essential for Vif function, suggesting that the association of Vif with membranes is likely to be important for its biological activity. The highly conserved regions at residues 103 to 115 and 142 to 150 were important for Vif function but did not affect membrane association, indicating that these regions are likely to be important for other, as-yet-unknown functions.
Goncalves
J
J
Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Jallepalli
P
P
Gabuzda
D H
DH
D000818:Animals; D001692:Biological Transport; D002451:Cell Compartmentation; D002478:Cells, Cultured; D003600:Cytosol / Q000737:chemistry; D004252:DNA Mutational Analysis; D005455:Fluorescent Antibody Technique; D016346:Gene Products, vif / Q000302:isolation & purification*; D005816:Genetic Complementation Test; D015497:HIV-1 / Q000737:chemistry* / Q000254:growth & development; D008565:Membrane Proteins / Q000302:isolation & purification*; D017384:Sequence Deletion; D013347:Subcellular Fractions / Q000737:chemistry; D014779:Virus Replication; D054320:vif Gene Products, Human Immunodeficiency Virus
D016346:Gene Products, vif; D008565:Membrane Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus