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Conformational changes in cell surface HIV-1 envelope glycoproteins are triggered by cooperation between cell surface

P L Jones1, T Korte, R Blumenthal

  • 1Section of Membrane Structure and Function, Laboratory of Experimental and Computational Biology, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA.

The Journal of Biological Chemistry
|February 7, 1998
PubMed

Insights

Human immunodeficiency virus type-1 (HIV-1) envelope glycoprotein gp120-gp41 undergoes rapid conformational changes upon CD4 binding. These changes are specific to the virus

Area of Science:

  • Virology
  • Cell Biology
  • Biochemistry

Background:

  • The human immunodeficiency virus type-1 (HIV-1) envelope glycoprotein (gp120-gp41) mediates viral entry into host cells.
  • Understanding the conformational changes of gp120-gp41 is crucial for developing effective antiviral strategies.

Purpose of the Study:

  • To investigate the CD4-induced conformational changes of HIV-1 gp120-gp41 in situ.
  • To determine the role of cell tropism in these conformational alterations and subsequent membrane fusion.

Main Methods:

  • Utilized 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid, a fluorescent probe, to measure conformational changes of gp120-gp41.
  • Employed CD4-expressing human T cell lines and macrophages to assess tropism-specific interactions.
  • Applied a dye transfer assay to evaluate membrane fusion and fusion pore formation.

Main Results:

  • CD4-expressing T cells induced rapid conformational changes in T cell-tropic gp120-gp41, but not macrophage-tropic strains.
  • Macrophages induced changes in macrophage-tropic gp120-gp41, with minimal changes in T cell-tropic strains.
  • Fusion occurred only when host cell tropism matched the viral envelope tropism, indicating cooperative receptor and co-receptor requirements.

Conclusions:

  • Conformational changes of HIV-1 gp120-gp41 are highly cooperative, requiring both CD4 receptor and co-receptor interactions.
  • Tropism-specific interactions between the viral envelope and host cell receptors are essential for membrane fusion and viral entry.

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