Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding.
The Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for virus entry into cells. Following endocytosis of EBOV, the GP1 domain is cleaved by cellular cathepsins in acidic endosomes, removing the glycan cap and exposing a binding site for the Niemann-Pick C1 (NPC1)...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2020-02-01
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| Series: | PLoS Biology |
| Online Access: | https://doi.org/10.1371/journal.pbio.3000626 |
| _version_ | 1828749141974450176 |
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| author | Dibyendu Kumar Das Uriel Bulow William E Diehl Natasha D Durham Fernando Senjobe Kartik Chandran Jeremy Luban James B Munro |
| author_facet | Dibyendu Kumar Das Uriel Bulow William E Diehl Natasha D Durham Fernando Senjobe Kartik Chandran Jeremy Luban James B Munro |
| author_sort | Dibyendu Kumar Das |
| collection | DOAJ |
| description | The Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for virus entry into cells. Following endocytosis of EBOV, the GP1 domain is cleaved by cellular cathepsins in acidic endosomes, removing the glycan cap and exposing a binding site for the Niemann-Pick C1 (NPC1) receptor. NPC1 binding to cleaved GP1 is required for entry. How this interaction translates to GP2 domain-mediated fusion of viral and endosomal membranes is not known. Here, using a bulk fluorescence dequenching assay and single-molecule Förster resonance energy transfer (smFRET)-imaging, we found that acidic pH, Ca2+, and NPC1 binding synergistically induce conformational changes in GP2 and permit virus-liposome lipid mixing. Acidic pH and Ca2+ shifted the GP2 conformational equilibrium in favor of an intermediate state primed for NPC1 binding. Glycan cap cleavage on GP1 enabled GP2 to transition from a reversible intermediate to an irreversible conformation, suggestive of the postfusion 6-helix bundle; NPC1 binding further promoted transition to the irreversible conformation. Thus, the glycan cap of GP1 may allosterically protect against inactivation of EBOV by premature triggering of GP2. |
| first_indexed | 2024-12-10T11:47:24Z |
| format | Article |
| id | doaj.art-05e0e4e295874e04b946f426f10d4105 |
| institution | Directory Open Access Journal |
| issn | 1544-9173 1545-7885 |
| language | English |
| last_indexed | 2024-12-10T11:47:24Z |
| publishDate | 2020-02-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Biology |
| spelling | doaj.art-05e0e4e295874e04b946f426f10d41052022-12-22T01:50:01ZengPublic Library of Science (PLoS)PLoS Biology1544-91731545-78852020-02-01182e300062610.1371/journal.pbio.3000626Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding.Dibyendu Kumar DasUriel BulowWilliam E DiehlNatasha D DurhamFernando SenjobeKartik ChandranJeremy LubanJames B MunroThe Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for virus entry into cells. Following endocytosis of EBOV, the GP1 domain is cleaved by cellular cathepsins in acidic endosomes, removing the glycan cap and exposing a binding site for the Niemann-Pick C1 (NPC1) receptor. NPC1 binding to cleaved GP1 is required for entry. How this interaction translates to GP2 domain-mediated fusion of viral and endosomal membranes is not known. Here, using a bulk fluorescence dequenching assay and single-molecule Förster resonance energy transfer (smFRET)-imaging, we found that acidic pH, Ca2+, and NPC1 binding synergistically induce conformational changes in GP2 and permit virus-liposome lipid mixing. Acidic pH and Ca2+ shifted the GP2 conformational equilibrium in favor of an intermediate state primed for NPC1 binding. Glycan cap cleavage on GP1 enabled GP2 to transition from a reversible intermediate to an irreversible conformation, suggestive of the postfusion 6-helix bundle; NPC1 binding further promoted transition to the irreversible conformation. Thus, the glycan cap of GP1 may allosterically protect against inactivation of EBOV by premature triggering of GP2.https://doi.org/10.1371/journal.pbio.3000626 |
| spellingShingle | Dibyendu Kumar Das Uriel Bulow William E Diehl Natasha D Durham Fernando Senjobe Kartik Chandran Jeremy Luban James B Munro Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. PLoS Biology |
| title | Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. |
| title_full | Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. |
| title_fullStr | Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. |
| title_full_unstemmed | Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. |
| title_short | Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. |
| title_sort | conformational changes in the ebola virus membrane fusion machine induced by ph ca2 and receptor binding |
| url | https://doi.org/10.1371/journal.pbio.3000626 |
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