Role of the SP2 Domain and Its Proteolytic Cleavage in HIV-1 Structural Maturation and Infectivity

Marco, Alex de; Heuser, Anke‐Mareil; Glass, Bärbel; Kräusslich, Hans‐Georg; Müller, Bárbara; Briggs, John

doi:10.1128/jvi.01704-12

Cited by 38 publications

(68 citation statements)

References 50 publications

(67 reference statements)

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“…Inhibition of PR activity and premature processing due to enhanced activation of the enzyme are detrimental for virus replication (16). An ordered sequence of PR cleavage events has been deduced from in vitro analyses (17)(18)(19); accordingly, mutational analyses revealed that even partial blocking of processing at individual sites impairs viral infectivity, and an ordered series of cleavage events within Gag is important for formation of a mature viral core (20)(21)(22); reviewed in reference 23).…”

mentioning

confidence: 99%

Induced Maturation of Human Immunodeficiency Virus

Matteı

Anders

Konvalinka

et al. 2014

J Virol

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HIV-1 assembles at the plasma membrane of virus-producing cells as an immature, noninfectious particle. Processing of the Gag and Gag-Pol polyproteins by the viral protease (PR) activates the viral enzymes and results in dramatic structural rearrangements within the virion-termed maturation-that are a prerequisite for infectivity. Despite its fundamental importance for viral replication, little is currently known about the regulation of proteolysis and about the dynamics and structural intermediates of maturation. This is due mainly to the fact that HIV-1 release and maturation occur asynchronously both at the level of individual cells and at the level of particle release from a single cell. Here, we report a method to synchronize HIV-1 proteolysis in vitro based on protease inhibitor (PI) washout from purified immature virions, thereby temporally uncoupling virus assembly and maturation. Drug washout resulted in the induction of proteolysis with cleavage efficiencies correlating with the off-rate of the respective PR-PI complex. Proteolysis of Gag was nearly complete and yielded the correct products with an optimal halflife (t 1/2 ) of ϳ5 h, but viral infectivity was not recovered. Failure to gain infectivity following PI washout may be explained by the observed formation of aberrant viral capsids and/or by pronounced defects in processing of the reverse transcriptase (RT) heterodimer associated with a lack of RT activity. Based on our results, we hypothesize that both the polyprotein processing dynamics and the tight temporal coupling of immature particle assembly and PR activation are essential for correct polyprotein processing and morphological maturation and thus for HIV-1 infectivity. IMPORTANCECleavage of the Gag and Gag-Pol HIV-1 polyproteins into their functional subunits by the viral protease activates the viral enzymes and causes major structural rearrangements essential for HIV-1 infectivity. This proteolytic maturation occurs concomitant with virus release, and investigation of its dynamics is hampered by the fact that virus populations in tissue culture contain particles at all stages of assembly and maturation. Here, we developed an inhibitor washout strategy to synchronize activation of protease in wild-type virus. We demonstrated that nearly complete Gag processing and resolution of the immature virus architecture are accomplished under optimized conditions. Nevertheless, most of the resulting particles displayed irregular morphologies, Gag-Pol processing was not faithfully reconstituted, and infectivity was not recovered. These data show that HIV-1 maturation is sensitive to the dynamics of processing and also that a tight temporal link between virus assembly and PR activation is required for correct polyprotein processing.

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confidence: 99%

Induced Maturation of Human Immunodeficiency Virus

Matteı

Anders

Konvalinka

et al. 2014

J Virol

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“…In conical capsids the genome is primarily located in the base of the cone, consistent with the experimental findings of Refs. 18,19,21,22 However, if the genome interacts attractively with the capsid wall, as is the case in the experiments of Ganser et al, 11 we find that with the same amount of genomic material and the same number of capsid proteins, the genome confinement free energy is slightly larger for a cone-shaped than that of a cylindrical capsid. This may explain why cones are less favorable than cylinders in in vitro HIV-1 experiments.…”

Section: Introductionmentioning

confidence: 63%

“…It has been suggested that while the viral protease cleaves the CA-NC link during maturation, incomplete cleaved links could be the reason why the RNA remains encapsulated in the mature capsid. 18,19 It is important to note that while the interaction between CA proteins is the driving force for Gag assembly in both the mature and immature hexagonal lattices, the free energy associated with the CA-CA interaction is thought to be weak, and the free energy of the CA-CA interaction in conical and cylindrical capsids has not yet been determined experimentally. To this end, in this paper, we only focus on the contribution of genome confinement free energy, assuming that the free energies due to CA-CA interaction between cylindrical and conical capsids are not considerable as they both appear in the in vitro studies in which no genome was present.…”

Section: Discussionmentioning

confidence: 99%

“…18,19,21,22 Note that due to the electrostatic interaction between the positively charged cleaved NC proteins and the negatively charged genome the solution can in some sense be considered near the θ conditions. For simplicity, thus we set the excluded volume interaction to zero, ν = 0.…”

Section: Modelmentioning

confidence: 99%

“…It is well-known that there is no attractive interaction between RNA and CA proteins. 18,19 There are a number of theoretical and computer simulation studies that investigate factors that contribute to the formation of conical capsids. The focus of prior work is on the elastic energy of the capsids, mostly in the absence of genome, and also on role of kinetic pathways towards assembly.…”

Section: Introductionmentioning

confidence: 99%

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Role of Genome in the Formation of Conical Retroviral Shells

et al. 2016

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Human immunodeficiency virus (HIV) capsid proteins spontaneously assemble around the genome into a protective protein shell called the capsid, which can take on a variety of shapes broadly classified as conical, cylindrical and irregular. The majority of capsids seen in in vivo studies are conical in shape, while in vitro experiments have shown a preference for cylindrical capsids. The factors involved in the selection of the unique shape of HIV capsids are not well understood, and in particular the impact of RNA on the formation of the capsid is not known. In this work, we study the role of the genome and its interaction with the capsid protein by modeling the genomic RNA through a mean-field theory. Our results show that the confinement free energy for a homopolymeric model genome confined in a conical capsid is

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Nucleocapsid Protein: A Desirable Target for Future Therapies Against HIV-1

Mori

Kovalenko

Lyonnais

et al. 2015

Current Topics in Microbiology and Immunology

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The currently available anti-HIV-1 therapeutics is highly beneficial to infected patients. However, clinical failures occur as a result of the ability of HIV-1 to rapidly mutate. One approach to overcome drug resistance is to target HIV-1 proteins that are highly conserved among phylogenetically distant viral strains and currently not targeted by available therapies. In this respect, the nucleocapsid (NC) protein, a zinc finger protein, is particularly attractive, as it is highly conserved and plays a central role in virus replication, mainly by interacting with nucleic acids. The compelling rationale for considering NC as a viable drug target is illustrated by the fact that point mutants of this protein lead to noninfectious viruses and by the inability to select viruses resistant to a first generation of anti-NC drugs. In our review, we discuss the most relevant properties and functions of NC, as well as recent developments of small molecules targeting NC. Zinc ejectors show strong antiviral activity, but are endowed with a low therapeutic index due to their lack of specificity, which has resulted in toxicity. Currently, they are mainly being investigated for use as topical microbicides. Greater specificity may be achieved by using non-covalent NC inhibitors (NCIs) targeting the hydrophobic platform at the top of the zinc fingers or key nucleic acid partners of NC. Within the last few years, innovative methodologies have been developed to identify NCIs. Though the antiviral activity of the identified NCIs needs still to be improved, these compounds strongly support the druggability of NC and pave the way for future structure-based design and optimization of efficient NCIs.

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Role of the SP2 Domain and Its Proteolytic Cleavage in HIV-1 Structural Maturation and Infectivity

Cited by 38 publications

References 50 publications

Induced Maturation of Human Immunodeficiency Virus

Induced Maturation of Human Immunodeficiency Virus

Role of Genome in the Formation of Conical Retroviral Shells

Nucleocapsid Protein: A Desirable Target for Future Therapies Against HIV-1

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