Rescue of HIV-1 Receptor Function through Cooperation between Different Forms of the CCR5 Chemokine Receptor

Chelli, Maurice; Alizon, Marc

doi:10.1074/jbc.m205394200

Cited by 13 publications

(10 citation statements)

References 64 publications

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“…The latter are CCR5 transfectants of a murine pre-B-cell lymphoma line (116), so that post-translational modifications of CCR5 may be subtly different from what happens in primary human cells. Again, there is precedent for chemokine receptors, including CCR5, existing in multiple isoforms and conformations (6,10,11,18,36,63,64,67,70). If this is the explanation, then full AD101 resistance involves HIV-1 acquiring the ability to use a distinctive configuration of CCR5 that, somehow, is not affected by AD101 and other small-molecule inhibitors while still being vulnerable to CCR5-specific MAbs and RANTES.…”

Section: Discussionmentioning

confidence: 99%

Genetic and Phenotypic Analyses of Human Immunodeficiency Virus Type 1 Escape from a Small-Molecule CCR5 Inhibitor

Kuhmann

Pugach

Kunstman

et al. 2004

J Virol

187

218

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, Proc. Natl. Acad. Sci. USA 99:395-400, 2002). The escape mutant, CC101.19, continued to use CCR5 for entry, but it was at least 20,000-fold more resistant to AD101 than the parental virus, CC1/85. We have now cloned the env genes from the the parental and escape mutant isolates and made chimeric infectious molecular clones that fully recapitulate the phenotypes of the corresponding isolates. Sequence analysis of the evolution of the escape mutants suggested that the most relevant changes were likely to be in the V3 loop of the gp120 glycoprotein. We therefore made a series of mutant viruses and found that full AD101 resistance was conferred by four amino acid changes in V3. Each change individually caused partial resistance when they were introduced into the V3 loop of a CC1/85 clone, but their impact was dependent on the gp120 context in which they were made. We assume that these amino acid changes alter how the HIV-1 Env complex interacts with CCR5. Perhaps unexpectedly, given the complete dependence of the escape mutant on CCR5 for entry, monomeric gp120 proteins expressed from clones of the fully resistant isolate failed to bind to CCR5 on the surface of L1.2-CCR5 cells under conditions where gp120 proteins from the parental virus and a partially AD101-resistant virus bound strongly. Hence, the full impact of the V3 substitutions may only be apparent at the level of the native Env complex.Several members of a new class of inhibitors based on blocking human immunodeficiency virus type 1 (HIV-1) entry into target cells are now in, or approaching, human clinical trials (8,52,77,80,85,90,98). These various compounds antagonize different stages in the multistep pathway by which HIV-1 fuses with susceptible cells. For example, the CD4-immunoglobulin G2 protein (CD4-IgG2; PRO 542) attaches to the viral envelope glycoprotein gp120 to prevent it from interacting with the CD4 receptor (3, 109). The T-20 and T-1249 peptides act later, by inhibiting conformational changes in the viral gp41 glycoprotein that are necessary for membrane fusion to be initiated (8,40,72,115). All these inhibitors cause plasma viremia reductions in HIV-1-infected people (8,49,53,62,66,71,80).A step in the entry process intermediate between gp120-CD4 attachment and gp41 conformational changes involves a coreceptor for gp120 (21,31,37,85,98). Thus, after gp120 has bound to CD4, it changes conformation to enable it to bind to a coreceptor from the G-protein-coupled receptor superfamily (21,31,37,85,98,107,116). The most physiologically relevant coreceptors are the chemokine receptors CCR5 or CXCR4, the former used by HIV-1 strains that usually dominate early in infection and the latter used by viruses that sometimes emerge several years later or that are detectable only transiently (21,31,85,99,122). The presence of viruses able to use CXCR4 (X4 strains) is associated with an accelerated disease course, due in part to the loss of naive CD4 ϩ T cells that express CXCR4 but not CCR5 (32,44,69). Viruses using CCR5 (R5 strains) target memory CD4 ϩ...

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Section: Discussionmentioning

confidence: 99%

Genetic and Phenotypic Analyses of Human Immunodeficiency Virus Type 1 Escape from a Small-Molecule CCR5 Inhibitor

Kuhmann

Pugach

Kunstman

et al. 2004

J Virol

187

218

View full text Add to dashboard Cite

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“…Moreover, receptor oligomerization is constitutive, i.e. independent of receptor activation, and does not require the N-terminal extracellular domain (36). By using a functional complementation approach we demonstrate that a CCR5-⌬NT mutant deficient in ligand binding undergoes GRK-mediated phosphorylation if this receptor is co-expressed together with a different receptor mutant that recruits receptor kinases to the CCR5 homooligomer at the plasma membrane (Fig.…”

Section: Discussionmentioning

confidence: 99%

G Protein-coupled Receptor Kinases Promote Phosphorylation and β-Arrestin-mediated Internalization of CCR5 Homo- and Hetero-oligomers

Hüttenrauch

Pollok-Kopp

Oppermann

2005

Journal of Biological Chemistry

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Expression levels of the chemokine receptor, CC chemokine receptor 5 (CCR5), at the cell surface determine cell susceptibility to HIV entry and infection. Cellular activation by CCR5 itself, but also by unrelated receptors leads to cross-phosphorylation and crossinternalization of CCR5. This study addresses the underlying molecular mechanisms of homologous and heterologous CCR5 regulation. As shown by bioluminescence resonance energy transfer experiments, CCR5 formed constitutive homo-as well as heterooligomeric complexes together with C5aR but not with the unrelated AT 1a R in living cells. Stimulation with CCL5 of RBL cells, which co-expressed CCR5 together with an N-terminally truncated CCR5-⌬NT mutant, resulted in both protein kinase C (PKC)-and G protein-coupled receptor (GPCR) kinase (GRK)-mediated crossphosphorylation of the mutant unligated receptor, as determined by phosphosite-specific monoclonal antibody. Similarly, both PKC and GRK cross-phosphorylated CCR5 in a heterologous manner after C5a stimulation of RBL-CCR5/C5aR cells, whereas AT 1a R stimulation resulted only in classical PKC-mediated CCR5 phosphorylation. Co-expression of CCR5-⌬NT together with a phosphorylation-deficient CCR5 mutant that neither binds ␤-arrestin nor undergoes internalization partially restored the CCL5-induced association of ␤-arrestin with the homo-oligomeric receptor complex and augmented cellular uptake of 125 I-CCL5. Co-expression of C5aR, but not of AT 1a R, promoted CCR5 co-internalization upon agonist stimulation by a mechanism independent of CCR5 phosphorylation. Co-internalization of phosphorylated CCR5 was also observed in C5a-stimulated macrophages. Finally, co-expression of a constitutively internalized C5aR-US28 CT mutant led to intracellular accumulation of CCR5 in the absence of ligand stimulation. These results show that GRKs and ␤-arrestin are involved in heterologous receptor regulation by cross-phosphorylating and co-internalizing unligated receptors within homo-or hetero-oligomeric protein complexes.Leukocytes express multiple pertussis toxin-sensitive chemoattractant receptors that may be engaged simultaneously or sequentially as these cells are recruited into tissue sites of inflammation. Interaction of such receptors with their cognate ligands results, among other cellular functions, in directional cell movement, integrin activation, and release of granular contents (1). Upon ligand binding, receptors also undergo adaptive changes, which include desensitization and internalization. Two major mechanisms of rapid receptor regulation have been discriminated, namely homologous (agonist-specific) and heterologous (agonist-nonspecific) desensitization, and both mechanisms are believed to be important in fine tuning leukocyte responses (2).Homologous desensitization involves phosphorylation of ligand-occupied receptors by members of the GPCR 3 kinase (GRK) family with, according to the current paradigm, essentially no effect on other receptors expressed in the same cell (3, 4). These kinases often phosphory...

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“…A number of studies have suggested that many GPCRs form homo-and heterodimers and that the dimerization contributes to modulation of receptor function (10). Dimer-forming receptors include (but are not limited to) ␤ 2 -adrenergic receptor (11), the ␦ opioid receptor (12), somatostatin receptors (13), CXCR4 (14), CCR2 (15), and CCR5 (16,17). The last three of these are chemokine receptors that mediate chemotaxis toward their ligands in a manner similar to FPR.…”

mentioning

confidence: 99%

Experimental Evidence for Lack of Homodimerization of the G Protein-Coupled Human N-Formyl Peptide Receptor

Gripentrog

Kantele

Jesaitis

et al. 2003

The Journal of Immunology

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A large number of G protein-coupled receptors have been shown to form homodimers based on a number of different techniques such as receptor coimmunoprecipitation, cross-linking, and fluorescence resonance energy transfer. In addition, functional assays of cells coexpressing a mutant receptor with a wild-type receptor have shown receptor phenotypes that can best be explained through dimerization. We asked whether the human neutrophil N-formyl peptide receptor (FPR) forms dimers in Chinese hamster ovary cells by coexpressing wild-type FPR with one of two mutants: D71A, which is uncoupled from G protein, and N297A, which has a defect in receptor phosphorylation and endocytosis. Experiments measuring chemotaxis, ligand-induced release of intracellular calcium, and p42/44 mitogen-activated protein kinase activation did not show an inhibitory effect of the coexpressed FPR D71A mutant. Coexpressed wild-type receptor was efficiently internalized, but failed to correct the endocytosis defects of the D71A and the N297A mutants. To explore the possibility that the mutations themselves prevented dimerization, we examined the coimmunoprecipitation of differentially epitope-tagged FPR. Immunoprecipitation of hemagglutinin-tagged FPR failed to coimmunoprecipitate coexpressed c-myc-tagged FPR and vice versa. Together, these data suggest that, unlike many other G protein-coupled receptors, FPR does not form homodimers.

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Rescue of HIV-1 Receptor Function through Cooperation between Different Forms of the CCR5 Chemokine Receptor

Cited by 13 publications

References 64 publications

Genetic and Phenotypic Analyses of Human Immunodeficiency Virus Type 1 Escape from a Small-Molecule CCR5 Inhibitor

Genetic and Phenotypic Analyses of Human Immunodeficiency Virus Type 1 Escape from a Small-Molecule CCR5 Inhibitor

G Protein-coupled Receptor Kinases Promote Phosphorylation and β-Arrestin-mediated Internalization of CCR5 Homo- and Hetero-oligomers

Experimental Evidence for Lack of Homodimerization of the G Protein-Coupled Human N-Formyl Peptide Receptor

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