Opposing Effects of Human Immunodeficiency Virus Type 1 Matrix Mutations Support a Myristyl Switch Model of Gag Membrane Targeting

Paillart, Jean-Christophe; Göttlinger, Heinrich G.

doi:10.1128/jvi.73.4.2604-2612.1999

Cited by 142 publications

(43 citation statements)

References 54 publications

(89 reference statements)

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“…By contrast, in macrophages infected with the MA WE-AA HIV-1 mutant, lower levels of intracellular CAp24 proteins and similar levels of extracellular CAp24 were observed compared to wt HIV-1 ( Figure 3D,E). Therefore, viral release was slightly higher for the MA WE-AA HIV-1 mutant than for wt HIV-1 ( Figure 3F), as described before (31). The results obtained from three independent donors showed a 1-to 1.5-fold increase of viral release for the mutant compared to wt HIV-1 (Table 1).…”

Section: Env Incorporation and Hiv-1 Infectivity Depend On The Integrsupporting

confidence: 78%

TIP47 is Required for the Production of Infectious HIV-1 Particles from Primary Macrophages

Bauby

López‐Vergès

Hoeffel

et al. 2010

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Macrophages are among the major targets of HIV-1 infection and play a key role in viral pathogenesis.Identification of the cellular cofactors involved in the production of infectious HIV-1 from macrophages is thus crucial. Here, we investigated the role of the cellular cofactor TIP47 in HIV-1 morphogenesis in primary macrophages. Using siRNA approach, we show that TIP47 is essential for HIV-1 infectivity and propagation. TIP47 silencing disrupts Gag and Env colocalization in macrophages. Moreover, mutations in HIV-1 Gag or Env, which abolish interaction with TIP47, impair HIV-1 propagation and infectivity preventing colocalization of Gag and Env, Gag and Env coimmunoprecipitation. Interestingly, disruption of Gag-TIP47 interaction by matrix mutation or TIP47 depletion also causes Gag to localize in scattered dots in the vicinity of the plasma membrane of macrophages. Therefore, TIP47 is required for the encounter between Gag and Env, and thus for the generation of infectious HIV-1 particles from primary macrophages.

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Section: Env Incorporation and Hiv-1 Infectivity Depend On The Integrsupporting

confidence: 78%

TIP47 is Required for the Production of Infectious HIV-1 Particles from Primary Macrophages

Bauby

López‐Vergès

Hoeffel

et al. 2010

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“…Fractions 3 and 4 contain membrane-bound material; non-membrane-bound proteins are recovered in fractions 9 and 10 (37) (see Materials and Methods). Consistent with previous data obtained in HeLa cells (37,39) approximately 40% of full-length Pr55 Gag was recovered in the membrane-containing fractions (Fig. 7), whereas approximately 3% of MA floated to fractions 3 and 4.…”

Section: Construction Of Hiv-1 Gag Truncation Mutantssupporting

confidence: 92%

“…We performed membrane flotation centrifugation (Fig. 7), which we and others have previously used to analyze steady-state HIV-1 Gag membrane binding (37,39,48). This method can distinguish oligomeric, nonmembrane-bound Gag complexes from membrane-bound Gag, a separation that cannot be achieved by conventional subcellular fractionation techniques.…”

Section: Construction Of Hiv-1 Gag Truncation Mutantsmentioning

confidence: 99%

Relationship between Human Immunodeficiency Virus Type 1 Gag Multimerization and Membrane Binding

Ono¹,

Demirov²,

Freed³

2000

J. Virol.

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The human immunodeficiency virus type 1 (HIV-1) Gag precursor, Pr55 Gag , is necessary and sufficient for the assembly and release of viruslike particles. Binding of Gag to membrane and Gag multimerization are both essential steps in virus assembly, yet the domains responsible for these events have not been fully defined. In addition, the relationship between membrane binding and Gag-Gag interaction remains to be elucidated. To investigate these issues, we analyzed, in vivo, the membrane-binding and assembly properties of a series of C-terminally truncated Gag mutants. Pr55 Gag was truncated at the C terminus of matrix (MAstop), between the N-and C-terminal domains of capsid (CA146stop), at the C terminus of capsid (p41stop), at the C terminus of p2 (p43stop), and after the N-terminal 35 amino acids of nucleocapsid (NC35stop). The ability of these truncated Gag molecules to assemble and release viruslike particles and their capacity to copackage into particles when coexpressed with full-length Gag were determined. We demonstrate that the amount of truncated Gag incorporated into particles is incrementally increased by extension from CA146 to NC35, suggesting that multiple sites in this region are involved in Gag multimerization. Using membrane flotation centrifugation, we observe that MA shows significantly reduced membrane binding relative to full-length Gag but that CA146 displays steady-state membrane-binding properties comparable to those of Pr55 Gag . The finding that the CA146 mutant, which contains only matrix and the N-terminal domain of capsid, exhibits levels of steady-state membrane binding equivalent to those of full-length Gag indicates that strong Gag-Gag interaction domains are not required for the efficient binding of HIV-1 Gag to membrane.

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“…Like other mammalian retrovirus matrix proteins, HIV-1 MA is myristoylated at its N-terminus, and myristoylation is essential for efficient membrane binding, virus assembly, and infectivity (Bryant and Ratner, 1990;Pal et al, 1990;Saad et al, 2006;Tang et al, 2004;. Studies support a myristoyl switch model for MA membrane association, in which the myristate group of PrGag inserts into membranes to promote binding, but that this fatty acid is retracted on proteolytic processing of PrGag, conferring a reduced membrane affinity for mature MA proteins (Hermuda-Matsumato and Resh, 1999;Paillart and Gottlinger, 1999;Spearman et al, 1997;Tang et al, 2004). Although the MA myristate is necessary for tight PrGag-membrane binding, it is not the only contributor.…”

Section: Introductionmentioning

confidence: 99%

Analysis of human immunodeficiency virus matrix domain replacements

et al. 2008

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The matrix (MA) domain of the HIV-1 structural precursor Gag (PrGag) protein targets PrGag proteins to membrane assembly sites, and facilitates incorporation of envelope proteins into virions. To evaluate the specific requirements for the MA membrane-binding domain (MBD) in HIV-1 assembly and replication, we examined viruses in which MA was replaced by alternative MBDs. Results demonstrated that the pleckstrin homology domains of AKT protein kinase and phospholipase C delta1 efficiently directed the assembly and release of virus-like particles (VLPs) from cells expressing chimeric proteins. VLP assembly and release also were mediated in a phorbol ester-dependent fashion by the cysteine-rich binding domain of phosphokinase Cgamma. Although alternative MBDs promoted VLP assembly and release, the viruses were not infectious. Notably, PrGag processing was reduced, while cleavage of GagPol precursors resulted in the accumulation of Pol-derived intermediates within virions. Our results indicate that the HIV-1 assembly machinery is flexible with regard to its means of membrane association, but that alternative MBDs can interfere with the elaboration of infectious virus cores.

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Opposing Effects of Human Immunodeficiency Virus Type 1 Matrix Mutations Support a Myristyl Switch Model of Gag Membrane Targeting

Cited by 142 publications

References 54 publications

TIP47 is Required for the Production of Infectious HIV-1 Particles from Primary Macrophages

TIP47 is Required for the Production of Infectious HIV-1 Particles from Primary Macrophages

Relationship between Human Immunodeficiency Virus Type 1 Gag Multimerization and Membrane Binding

Analysis of human immunodeficiency virus matrix domain replacements

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