Cargando…
Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes
Phosphatidylinositol 4,5-bisphosphate (PIP2) is critical for HIV-1 virus assembly. The viral membrane is enriched in PIP2, suggesting that the virus assembles at PIP2-rich microdomains. We showed previously that in model membranes PIP2 can form nanoscopic clusters bridged by multivalent cations. Her...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2020
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262684/ https://www.ncbi.nlm.nih.gov/pubmed/32739462 http://dx.doi.org/10.1016/j.jmb.2020.07.018 |
_version_ | 1783719231565594624 |
---|---|
author | Wen, Yi Feigenson, Gerald W. Vogt, Volker M. Dick, Robert A. |
author_facet | Wen, Yi Feigenson, Gerald W. Vogt, Volker M. Dick, Robert A. |
author_sort | Wen, Yi |
collection | PubMed |
description | Phosphatidylinositol 4,5-bisphosphate (PIP2) is critical for HIV-1 virus assembly. The viral membrane is enriched in PIP2, suggesting that the virus assembles at PIP2-rich microdomains. We showed previously that in model membranes PIP2 can form nanoscopic clusters bridged by multivalent cations. Here, using purified proteins we quantitated the binding of HIV-1 Gag-related proteins to giant unilamellar vesicles containing either clustered or free PIP2. Myristoylated MA strongly preferred binding to clustered PIP2. By contrast, unmyristoylated HIV-1 MA, RSV MA, and a PH domain all preferred to interact with free PIP2. We also found that HIV-1 Gag multimerization promotes PIP2 clustering. Truncated Gag proteins comprising the MA, CA, and SP domains (MACASP) or the MA and CA domains (MACA) induced self-quenching of acyl chain-labeled fluorescent PIP2 in liposomes, implying clustering. However, HIV-1 MA itself did not induce PIP2 clustering. A CA inter-hexamer dimer interface mutation led to a loss of induced PIP2 clustering in MACA, indicating the importance of protein multimerization. Cryo-electron tomography of liposomes with bound MACA showed an amorphous protein layer on the membrane surface. Thus, it appears that while protein–protein interactions are required for PIP2 clustering, formation of a regular lattice is not. Protein-induced PIP2 clustering and multivalent cation-induced PIP2 clustering are additive. Taken together, these results provide the first evidence that HIV-1 Gag can selectively target pre-existing PIP2-enriched domains of the plasma membrane for viral assembly, and that Gag multimerization can further enrich PIP2 at assembly sites. These effects could explain the observed PIP2 enrichment in HIV-1. |
format | Online Article Text |
id | pubmed-8262684 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
record_format | MEDLINE/PubMed |
spelling | pubmed-82626842021-07-07 Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes Wen, Yi Feigenson, Gerald W. Vogt, Volker M. Dick, Robert A. J Mol Biol Article Phosphatidylinositol 4,5-bisphosphate (PIP2) is critical for HIV-1 virus assembly. The viral membrane is enriched in PIP2, suggesting that the virus assembles at PIP2-rich microdomains. We showed previously that in model membranes PIP2 can form nanoscopic clusters bridged by multivalent cations. Here, using purified proteins we quantitated the binding of HIV-1 Gag-related proteins to giant unilamellar vesicles containing either clustered or free PIP2. Myristoylated MA strongly preferred binding to clustered PIP2. By contrast, unmyristoylated HIV-1 MA, RSV MA, and a PH domain all preferred to interact with free PIP2. We also found that HIV-1 Gag multimerization promotes PIP2 clustering. Truncated Gag proteins comprising the MA, CA, and SP domains (MACASP) or the MA and CA domains (MACA) induced self-quenching of acyl chain-labeled fluorescent PIP2 in liposomes, implying clustering. However, HIV-1 MA itself did not induce PIP2 clustering. A CA inter-hexamer dimer interface mutation led to a loss of induced PIP2 clustering in MACA, indicating the importance of protein multimerization. Cryo-electron tomography of liposomes with bound MACA showed an amorphous protein layer on the membrane surface. Thus, it appears that while protein–protein interactions are required for PIP2 clustering, formation of a regular lattice is not. Protein-induced PIP2 clustering and multivalent cation-induced PIP2 clustering are additive. Taken together, these results provide the first evidence that HIV-1 Gag can selectively target pre-existing PIP2-enriched domains of the plasma membrane for viral assembly, and that Gag multimerization can further enrich PIP2 at assembly sites. These effects could explain the observed PIP2 enrichment in HIV-1. 2020-07-31 2020-09-04 /pmc/articles/PMC8262684/ /pubmed/32739462 http://dx.doi.org/10.1016/j.jmb.2020.07.018 Text en https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ). |
spellingShingle | Article Wen, Yi Feigenson, Gerald W. Vogt, Volker M. Dick, Robert A. Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title | Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title_full | Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title_fullStr | Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title_full_unstemmed | Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title_short | Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes |
title_sort | mechanisms of pi(4,5)p2 enrichment in hiv-1 viral membranes |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262684/ https://www.ncbi.nlm.nih.gov/pubmed/32739462 http://dx.doi.org/10.1016/j.jmb.2020.07.018 |
work_keys_str_mv | AT wenyi mechanismsofpi45p2enrichmentinhiv1viralmembranes AT feigensongeraldw mechanismsofpi45p2enrichmentinhiv1viralmembranes AT vogtvolkerm mechanismsofpi45p2enrichmentinhiv1viralmembranes AT dickroberta mechanismsofpi45p2enrichmentinhiv1viralmembranes |