Uncoating of the metastable HIV-1 capsid is a tightly regulated disassembly process required for release of the viral cDNA prior to nuclear import. To understand the intrinsic capsid disassembly pathway and how it can be modulated, we have developed a single-particle fluorescence microscopy method to follow the real-time uncoating kinetics of authentic HIV capsids in vitro immediately after permeabilizing the viral membrane. Opening of the first defect in the lattice is the rate-limiting step of uncoating, which is followed by rapid, catastrophic collapse. The capsid-binding inhibitor PF74 accelerates capsid opening but stabilizes the remaining lattice. In contrast, binding of a polyanion to a conserved arginine cluster in the lattice strongly delays initiation of uncoating but does not prevent subsequent lattice disassembly. Our observations suggest that different stages of uncoating can be controlled independently with the interplay between different capsid-binding regulators likely to determine the overall uncoating kinetics.
- Stuart Turville
- Till Böcking
- Till Böcking
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Wesley I Sundquist, University of Utah School of Medicine, United States
© 2018, Márquez et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structural and biophysical studies help to follow the disassembly of the HIV-1 capsid in vitro, and reveal the role of a small molecule called IP6 in regulating capsid stability.