The Experts below are selected from a list of 23800908 Experts worldwide ranked by ideXlab platform
Xavier Hanoulle - One of the best experts on this subject based on the ideXlab platform.
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Cyclophilin A allows the allosteric regulation of a structural motif in the disordered domain 2 of NS5A and thereby fine-tunes HCV RNA replication
Journal of Biological Chemistry, 2019Co-Authors: Marie Dujardin, Vanesa Madan, Neha Gandhi, François-xavier Cantrelle, Hélène Launay, Isabelle Huvent, Ralf Bartenschlager, Guy Lippens, Xavier HanoulleAbstract:Implicated in numerous human diseases, intrinsically disordered proteins (IDPs) are dynamic ensembles of interconverting conformers that often contain many proline residues. Whether and how proline conformation regulates the functional aspects of IDPs remains an open question, however. Here, we studied the disordered domain 2 of nonstructural protein 5A (NS5A-D2) of hepatitis C virus (HCV). NS5A-D2 comprises a short structural motif (PW-turn) embedded in a proline-rich sequence , whose interaction with the human prolyl isomerase cyclophilin A (CypA) is essential for viral RNA replication. Using NMR, we show here that the PW-turn motif exists in a conformational equilibrium between folded and disordered states. We found that the fraction of conformers in the NS5A-D2 ensemble that adopt the structured motif is allosteri-cally modulated both by the cis/trans isomerization of the surrounding prolines that are CypA substrates and by substitutions conferring resistance to cyclophilin inhibitor. Moreover, we noted that this fraction is directly correlated with HCV RNA replication efficiency. We conclude that CypA can fine-tune the dynamic ensemble of the disordered NS5A-D2, thereby regulating viral RNA replication efficiency.
Jayasri Das Sarma - One of the best experts on this subject based on the ideXlab platform.
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one proline deletion in the fusion peptide of neurotropic mouse hepatitis virus mhv restricts retrograde axonal transport and neurodegeneration
Journal of Biological Chemistry, 2020Co-Authors: Saurav Saswat Rout, Manmeet Singh, Kenneth S Shindler, Jayasri Das SarmaAbstract:Mouse hepatitis virus (MHV;murine coronavirus [M-CoV]) causes meningoencephalitis, myelitis, and optic neuritis followed by axonal loss and demyelination This murine virus is used as a common model to study both acute and chronic virus-induced demyelination in the central nervous system Studies with recombinant MHV strains that differ in the gene encoding the spike protein have demonstrated that the spike has a role in both MHV pathogenesis and retrograde axonal transport Fusion peptides (FPs) in the spike protein play a key role in MHV pathogenesis In a previous study of the effect of deleting a single proline residue in the FP of a demyelinating MHV strain, we found that two central, consecutive prolines are important for cell-cell fusion and pathogenesis The dihedral fluctuation of the FP was showed to be repressed whenever two consecutive prolines (PP) were present, in contrast to the presence of a single proline (P) in the chain Using this proline-deleted MHV strain, here we investigated whether intracranial injection of this strain can induce optic neuritis by retrograde axonal transport from the brain to the retina through the optic nerve We observed that the proline-deleted recombinant MHV strain is restricted to the optic nerve, is unable to translocate to the retina, and causes only minimal demyelination and no neuronal death We conclude that an intact proline dyad in the FP of the recombinant demyelinating MHV strain plays a crucial role in translocation of the virus through axons and subsequent neurodegeneration
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a proline insertion deletion in the spike glycoprotein fusion peptide of mouse hepatitis virus strongly alters neuropathology
Journal of Biological Chemistry, 2019Co-Authors: Manmeet Singh, Abhinoy Kishore, Dibyajyoti Maity, Punnepalli Sunanda, Bankala Krishnarjuna, Sreeparna Vappala, Srinivasarao Raghothama, Lawrence C Kenyon, Debnath Pal, Jayasri Das SarmaAbstract:Fusion peptides (FPs) in spike proteins are key players mediating early events in cell-to-cell fusion, vital for intercellular viral spread. A proline residue located at the central FP region has often been suggested to have a distinctive role in this fusion event. The spike glycoprotein from strain RSA59 (PP) of mouse hepatitis virus (MHV) contains two central, consecutive prolines in the FP. Here, we report that deletion of one of these proline residues, resulting in RSA59 (P), significantly affected neural cell syncytia formation and viral titers postinfection in vitro Transcranial inoculation of C57Bl/6 mice with RSA59 (PP) or RSA59 (P) yielded similar degrees of necrotizing hepatitis and meningitis, but only RSA59 (PP) produced widespread encephalitis that extended deeply into the brain parenchyma. By day 6 postinfection, both virus variants were mostly cleared from the brain. Interestingly, inoculation with the RSA59 (P)-carrying MHV significantly reduced demyelination at the chronic stage. We also found that the presence of two consecutive prolines in FP promotes a more ordered, compact, and rigid structure in the spike protein. These effects on FP structure were due to proline's unique stereochemical properties intrinsic to its secondary amino acid structure, revealed by molecular dynamics and NMR experiments. We therefore propose that the differences in the severity of encephalitis and demyelination between RSA59 (PP) and RSA59 (P) arise from the presence or absence, respectively, of the two consecutive prolines in FP. Our studies define a structural determinant of MHV entry in the brain parenchyma important for altered neuropathogenesis.
Marius Sudol - One of the best experts on this subject based on the ideXlab platform.
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characterization of the ww domain of human yes associated protein and its polyproline containing ligands
Journal of Biological Chemistry, 1997Co-Authors: Henry I Chen, Aaron Einbond, Sahngjune Kwak, Hillary Linn, Edward K Koepf, Scott A Peterson, Marius SudolAbstract:We had previously identified the WW domain as a novel globular domain that is composed of 38-40 semiconserved amino acids and is involved in mediating protein-protein interaction. The WW domain is shared by proteins of diverse functions including structural, regulatory, and signaling proteins in yeast, nematode, and mammals. Functionally it is similar to the Src homology 3 domain in that it binds polyproline ligands. By screening a 16-day mouse embryo expression library, we identified two putative ligands of the WW domain of Yes kinase-associated protein which we named WW domain-binding proteins 1 and 2. These proteins interacted with the WW domain via a short proline-rich motif with the consensus sequence of four consecutive prolines followed by a tyrosine. Herein, we report the cDNA cloning and characterization of the human orthologs of WW domain-binding proteins 1 and 2. The products encoded by these cDNA clones represent novel proteins with no known function. Furthermore, these proteins show no homology to each other except for a proline-rich motif. By fluorescence in situ hybridization on human metaphase chromosomes, we mapped the human genes for WW domain-binding proteins 1 and 2 to chromosomes 2p12 and 17q25, respectively. In addition, using site-directed mutagenesis, we determined which residues in the WW domain of Yes kinase-associated protein are critical for binding. Finally, by synthesizing peptides in which the various positions of the four consecutive proline-tyrosine motif and the five surrounding residues were replaced by all possible amino acid residues, we further elucidated the binding requirements of this motif.
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structure of the ww domain of a kinase associated protein complexed with a proline rich peptide
Nature, 1996Co-Authors: Maria J Macias, Marius Sudol, Maija Hyvönen, Johan Schultz, Matti Saraste, Eugenio Baraldi, Hartmut OschkinatAbstract:THE WW domain is a new protein module with two highly conserved tryptophans that binds proline-rich peptide motifs in vitro. It is present in a number of signalling and regulatory proteins, often in several copies1–3. Here we investigate the solution structure of the WW domain of human YAP65 (for Yes kinase-associated protein) in complex with proline-rich peptides containing the core motif PPxY (ref. 4). The structure of the domain with the bound peptide GTPPPPYTVG is a slightly curved, three-stranded, antiparallel β-sheet. Two prolines pack against the first tryptophan, forming a hydrophobic buckle on the convex side of the sheet. The concave side has three exposed hydrophobic residues (tyrosine, tryptophan and leucine) which form the binding site for the ligand. A non-conserved isoleucine in the amino-terminal flanking region covers a hydrophobic patch and stabilizes the WW domain of human YAP65 in vitro. The structure of the WW domain differs from that of the SH3 domain and reveals a new design for a protein module that uses stacked aromatic surface residues to arrange a binding site for proline-rich peptides.
Marie Dujardin - One of the best experts on this subject based on the ideXlab platform.
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Cyclophilin A allows the allosteric regulation of a structural motif in the disordered domain 2 of NS5A and thereby fine-tunes HCV RNA replication
Journal of Biological Chemistry, 2019Co-Authors: Marie Dujardin, Vanesa Madan, Neha Gandhi, François-xavier Cantrelle, Hélène Launay, Isabelle Huvent, Ralf Bartenschlager, Guy Lippens, Xavier HanoulleAbstract:Implicated in numerous human diseases, intrinsically disordered proteins (IDPs) are dynamic ensembles of interconverting conformers that often contain many proline residues. Whether and how proline conformation regulates the functional aspects of IDPs remains an open question, however. Here, we studied the disordered domain 2 of nonstructural protein 5A (NS5A-D2) of hepatitis C virus (HCV). NS5A-D2 comprises a short structural motif (PW-turn) embedded in a proline-rich sequence , whose interaction with the human prolyl isomerase cyclophilin A (CypA) is essential for viral RNA replication. Using NMR, we show here that the PW-turn motif exists in a conformational equilibrium between folded and disordered states. We found that the fraction of conformers in the NS5A-D2 ensemble that adopt the structured motif is allosteri-cally modulated both by the cis/trans isomerization of the surrounding prolines that are CypA substrates and by substitutions conferring resistance to cyclophilin inhibitor. Moreover, we noted that this fraction is directly correlated with HCV RNA replication efficiency. We conclude that CypA can fine-tune the dynamic ensemble of the disordered NS5A-D2, thereby regulating viral RNA replication efficiency.
Manmeet Singh - One of the best experts on this subject based on the ideXlab platform.
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one proline deletion in the fusion peptide of neurotropic mouse hepatitis virus mhv restricts retrograde axonal transport and neurodegeneration
Journal of Biological Chemistry, 2020Co-Authors: Saurav Saswat Rout, Manmeet Singh, Kenneth S Shindler, Jayasri Das SarmaAbstract:Mouse hepatitis virus (MHV;murine coronavirus [M-CoV]) causes meningoencephalitis, myelitis, and optic neuritis followed by axonal loss and demyelination This murine virus is used as a common model to study both acute and chronic virus-induced demyelination in the central nervous system Studies with recombinant MHV strains that differ in the gene encoding the spike protein have demonstrated that the spike has a role in both MHV pathogenesis and retrograde axonal transport Fusion peptides (FPs) in the spike protein play a key role in MHV pathogenesis In a previous study of the effect of deleting a single proline residue in the FP of a demyelinating MHV strain, we found that two central, consecutive prolines are important for cell-cell fusion and pathogenesis The dihedral fluctuation of the FP was showed to be repressed whenever two consecutive prolines (PP) were present, in contrast to the presence of a single proline (P) in the chain Using this proline-deleted MHV strain, here we investigated whether intracranial injection of this strain can induce optic neuritis by retrograde axonal transport from the brain to the retina through the optic nerve We observed that the proline-deleted recombinant MHV strain is restricted to the optic nerve, is unable to translocate to the retina, and causes only minimal demyelination and no neuronal death We conclude that an intact proline dyad in the FP of the recombinant demyelinating MHV strain plays a crucial role in translocation of the virus through axons and subsequent neurodegeneration
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a proline insertion deletion in the spike glycoprotein fusion peptide of mouse hepatitis virus strongly alters neuropathology
Journal of Biological Chemistry, 2019Co-Authors: Manmeet Singh, Abhinoy Kishore, Dibyajyoti Maity, Punnepalli Sunanda, Bankala Krishnarjuna, Sreeparna Vappala, Srinivasarao Raghothama, Lawrence C Kenyon, Debnath Pal, Jayasri Das SarmaAbstract:Fusion peptides (FPs) in spike proteins are key players mediating early events in cell-to-cell fusion, vital for intercellular viral spread. A proline residue located at the central FP region has often been suggested to have a distinctive role in this fusion event. The spike glycoprotein from strain RSA59 (PP) of mouse hepatitis virus (MHV) contains two central, consecutive prolines in the FP. Here, we report that deletion of one of these proline residues, resulting in RSA59 (P), significantly affected neural cell syncytia formation and viral titers postinfection in vitro Transcranial inoculation of C57Bl/6 mice with RSA59 (PP) or RSA59 (P) yielded similar degrees of necrotizing hepatitis and meningitis, but only RSA59 (PP) produced widespread encephalitis that extended deeply into the brain parenchyma. By day 6 postinfection, both virus variants were mostly cleared from the brain. Interestingly, inoculation with the RSA59 (P)-carrying MHV significantly reduced demyelination at the chronic stage. We also found that the presence of two consecutive prolines in FP promotes a more ordered, compact, and rigid structure in the spike protein. These effects on FP structure were due to proline's unique stereochemical properties intrinsic to its secondary amino acid structure, revealed by molecular dynamics and NMR experiments. We therefore propose that the differences in the severity of encephalitis and demyelination between RSA59 (PP) and RSA59 (P) arise from the presence or absence, respectively, of the two consecutive prolines in FP. Our studies define a structural determinant of MHV entry in the brain parenchyma important for altered neuropathogenesis.
