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Human immunodeficiency virus type 1 matrix inhibits and confers cooperativity on gag precursor-membrane interactions

David Perez-Caballero1, Theodora Hatziioannou, Juan Martin-Serrano

  • 1Aaron Diamond AIDS Research Center and the Rockefeller University, New York, New York 10016, USA.

Journal of Virology
|August 17, 2004
PubMed

Insights

The HIV-1 matrix (MA) globular head blocks a plasma membrane targeting signal. Gag multimerization relieves this block, enabling cooperative HIV-1 assembly at the cell membrane.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Human immunodeficiency virus type 1 (HIV-1) particle formation depends on Gag multimerization and membrane binding.
  • The precise mechanisms and minimal signals for plasma membrane targeting by HIV-1 Gag remain incompletely understood.
  • The role of the matrix (MA) domain, particularly its globular head, in membrane association is unclear.

Purpose of the Study:

  • To identify the minimal plasma membrane-specific targeting signal for HIV-1 Gag.
  • To elucidate the role of the MA globular head in regulating Gag membrane association.
  • To investigate how Gag multimerization influences membrane targeting and cooperativity.

Main Methods:

  • Analysis of Gag deletion mutants using membrane flotation assays.
  • Microscopic examination of Gag localization and multimerization.
  • Biochemical characterization of Gag-membrane interactions.

Main Results:

  • The N-terminal six residues of the MA domain contain a plasma membrane-specific targeting signal.
  • The MA globular head acts as an inhibitor of this targeting signal.
  • Gag multimerization relieves MA-mediated inhibition, leading to concentration-dependent and cooperative Gag-membrane association.

Conclusions:

  • HIV-1 Gag utilizes a novel mechanism where the MA globular head regulates membrane targeting.
  • Gag multimerization is crucial for overcoming MA-mediated inhibition and achieving efficient membrane binding.
  • This regulated cooperativity likely plays a role in the temporal and spatial control of HIV-1 assembly.

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