Maturation-dependent HIV-1 surface protein redistribution revealed by fluorescence nanoscopy

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Human immunodeficiency virus type 1 (HIV-1) requires morphological maturation after budding for infectivity.
• Maturation involves the proteolysis of the structural polyprotein Gag.
• The distribution of viral envelope (Env) glycoproteins on the virion surface is critical for viral entry.

Purpose of the Study:

• To investigate the distribution of HIV-1 Env glycoproteins during viral maturation.
• To correlate Env surface distribution with viral entry efficiency.
• To understand the relationship between internal Gag processing and external Env organization.

Main Methods:

• Stimulated emission depletion (STED) superresolution fluorescence microscopy was used to visualize Env distribution on individual HIV-1 particles.
• Correlation analysis was performed between Env surface clustering and viral entry efficiency.

Main Results:

• HIV-1 maturation involves Env glycoprotein clustering on the virion surface.
• Env clustering is dependent on the Gag-interacting Env tail.
• Rearrangements of the internal protein lattice facilitate changes in the virus surface.
• A correlation exists between Env surface clustering and viral entry efficiency, indicating a link between internal and external viral structure.

Conclusions:

• Gag proteolysis-dependent clustering of Env trimers is a key aspect of HIV-1 maturation.
• This clustering mechanism is essential for preparing the virus surface for productive entry.
• The study reveals a coupling between the internal viral structure and the external Env protein organization during maturation.