Human immunodeficiency virus type 1 Vpu protein regulates the formation of intracellular gp160-CD4 complexes.
Intracellular transport and processing of the human immunodeficiency virus type 1 (HIV-1) envelope precursor glycoprotein, gp160, proceeds via the endoplasmic reticulum and Golgi complex and involves proteolytic processing of gp160 into the mature virion components, gp120 and gp41. We found that coexpression of gp160 and human CD4 in HeLa cells severely impaired gp120 production due to the formation of intracellular gp160-CD4 complexes. This CD4-mediated inhibition of gp160 processing was alleviated by coexpression of the HIV-1-encoded Vpu protein. The coexpression of Vpu and CD4 in the presence of gp160 resulted in increased degradation of CD4. Although the precise mechanism(s) responsible for the Vpu effect is presently unclear, our findings suggest that Vpu may destabilize intracellular gp160-CD4 complexes.
Willey
R L
RL
Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Maldarelli
F
F
Martin
M A
MA
Strebel
K
K
D015704:CD4 Antigens / Q000378:metabolism*; D015686:Gene Products, env / Q000378:metabolism*; D019302:HIV Envelope Protein gp160; D015497:HIV-1 / Q000378:metabolism*; D006367:HeLa Cells; D054298:Human Immunodeficiency Virus Proteins; D006801:Humans; D011233:Precipitin Tests; D011498:Protein Precursors / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins / Q000378:metabolism*; D000086082:Viroporin Proteins
D015704:CD4 Antigens; D015686:Gene Products, env; D019302:HIV Envelope Protein gp160; D054298:Human Immunodeficiency Virus Proteins; D011498:Protein Precursors; D054334:Viral Regulatory and Accessory Proteins; C514859:vpu protein, Human immunodeficiency virus 1; D000086082:Viroporin Proteins