EAP45 association with budding HIV-1: Kinetics and domain requirements

Area of Science:

• Cell Biology
• Virology
• Molecular Biology

Background:

• Viruses, including Human Immunodeficiency Virus (HIV), exploit the host cell's Endosomal Sorting Complexes Required for Transport (ESCRT) machinery for efficient viral particle release (budding).
• Previous biochemical studies confirmed the involvement of ESCRT-II in HIV-1 budding and identified key molecular domains responsible for this interaction.

Purpose of the Study:

• To investigate the role and localization of the ESCRT-II component EAP45 during HIV-1 budding.
• To define the specific molecular domains of EAP45 critical for viral budding and compare its function in viral processes versus cellular processes like cytokinesis.

Main Methods:

• Utilized SNAP-tag fluorescent labeling for visualizing EAP45 localization.
• Employed fixed and live-cell imaging techniques to observe EAP45 dynamics.
• Investigated the functional importance of EAP45's N-terminal H0 domain and the Glue domain.

Main Results:

• Demonstrated that EAP45 colocalizes with the HIV protein Gag at the plasma membrane in a manner similar to ALIX.
• Provided evidence for the potential packaging of EAP45 within HIV virions.
• Confirmed the critical role of EAP45's N-terminus, particularly the H0 domain, in the viral budding process.
• Showed that the Glue domain of EAP45 is more important for recruitment during cytokinesis, highlighting distinct viral and cellular recruitment mechanisms.

Conclusions:

• EAP45 is a key ESCRT-II component involved in HIV-1 budding, with its domains having specialized functions.
• Viral recruitment mechanisms utilizing EAP45 differ from those employed during cellular cytokinesis.
• These findings suggest potential for developing targeted antiviral therapies that selectively inhibit viral budding without disrupting essential cellular functions.