Evidence for cell-surface association between fusin and the CD4-gp120 complex in human cell lines.
Accessory cell-surface molecules involved in the entry of human immunodeficiency virus-type 1 into cells have recently been identified and shown to belong to the family of chemokine receptors. Treatment of human cell lines with soluble monomeric gp120 at 37 degrees C induced an association between the surface CD4-gp120 complex and a 45-kilodalton protein, which can be down-modulated by the phorbol ester phorbol 12-myristate 13-acetate. The three proteins were coprecipitated from the cell membranes with antibodies to CD4 or to gp120. The 45-kilodalton protein comigrated with fusin on sodium dodecyl sulfate gels and reacted with rabbit antisera to fusin in protein immunoblots. No 45-kilodalton protein could be coprecipitated from similarly treated nonhuman cells. However, infection of 3T3.CD4.401 cells with vaccinia-fusin recombinant virus (vCBYF1), followed by gp120 treatment, resulted in coprecipitation of fusin and CD4.401 molecules from their membranes. Together these data provide evidence for physical association between fusin and the CD4-gp120 complex on cell membranes.
Lapham
C K
CK
Division of Viral Products, Center for Biologics Evaluation and Research (CBER), Food and Drug Administration, 8800 Rockville Pike, Bethesda, MD 20892, USA.
Ouyang
J
J
Chandrasekhar
B
B
Nguyen
N Y
NY
Dimitrov
D S
DS
Golding
H
H
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D015704:CD4 Antigens / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D015726:Giant Cells; D015699:HIV Envelope Protein gp120 / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011233:Precipitin Tests; D019718:Receptors, CXCR4; D015728:Receptors, HIV / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D013601:T-Lymphocytes; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014616:Vaccinia virus / Q000235:genetics / Q000502:physiology
D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D008565:Membrane Proteins; D019718:Receptors, CXCR4; D015728:Receptors, HIV; D013755:Tetradecanoylphorbol Acetate