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Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection
The causative agent of Legionnaires’ disease, Legionella pneumophila, replicates in amoebae and macrophages in a distinct membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation is governed by the bacterial Icm/Dot type IV secretion system that translocates ~300 different...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society of Microbiology
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903275/ https://www.ncbi.nlm.nih.gov/pubmed/24473127 http://dx.doi.org/10.1128/mBio.00839-13 |
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author | Weber, Stephen Wagner, Maria Hilbi, Hubert |
author_facet | Weber, Stephen Wagner, Maria Hilbi, Hubert |
author_sort | Weber, Stephen |
collection | PubMed |
description | The causative agent of Legionnaires’ disease, Legionella pneumophila, replicates in amoebae and macrophages in a distinct membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation is governed by the bacterial Icm/Dot type IV secretion system that translocates ~300 different “effector” proteins into host cells. Some of the translocated effectors anchor to the LCV membrane via phosphoinositide (PI) lipids. Here, we use the soil amoeba Dictyostelium discoideum, producing fluorescent PI probes, to analyze the LCV PI dynamics by live-cell imaging. Upon uptake of wild-type or Icm/Dot-deficient L. pneumophila, PtdIns(3,4,5)P(3) transiently accumulated for an average of 40 s on early phagosomes, which acquired PtdIns(3)P within 1 min after uptake. Whereas phagosomes containing ΔicmT mutant bacteria remained decorated with PtdIns(3)P, more than 80% of wild-type LCVs gradually lost this PI within 2 h. The process was accompanied by a major rearrangement of PtdIns(3)P-positive membranes condensing to the cell center. PtdIns(4)P transiently localized to early phagosomes harboring wild-type or ΔicmT L. pneumophila and was cleared within minutes after uptake. During the following 2 h, PtdIns(4)P steadily accumulated only on wild-type LCVs, which maintained a discrete PtdIns(4)P identity spatially separated from calnexin-positive endoplasmic reticulum (ER) for at least 8 h. The separation of PtdIns(4)P-positive and ER membranes was even more pronounced for LCVs harboring ΔsidC-sdcA mutant bacteria defective for ER recruitment, without affecting initial bacterial replication in the pathogen vacuole. These findings elucidate the temporal and spatial dynamics of PI lipids implicated in LCV formation and provide insight into host cell membrane and effector protein interactions. |
format | Online Article Text |
id | pubmed-3903275 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | American Society of Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-39032752014-01-30 Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection Weber, Stephen Wagner, Maria Hilbi, Hubert mBio Research Article The causative agent of Legionnaires’ disease, Legionella pneumophila, replicates in amoebae and macrophages in a distinct membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation is governed by the bacterial Icm/Dot type IV secretion system that translocates ~300 different “effector” proteins into host cells. Some of the translocated effectors anchor to the LCV membrane via phosphoinositide (PI) lipids. Here, we use the soil amoeba Dictyostelium discoideum, producing fluorescent PI probes, to analyze the LCV PI dynamics by live-cell imaging. Upon uptake of wild-type or Icm/Dot-deficient L. pneumophila, PtdIns(3,4,5)P(3) transiently accumulated for an average of 40 s on early phagosomes, which acquired PtdIns(3)P within 1 min after uptake. Whereas phagosomes containing ΔicmT mutant bacteria remained decorated with PtdIns(3)P, more than 80% of wild-type LCVs gradually lost this PI within 2 h. The process was accompanied by a major rearrangement of PtdIns(3)P-positive membranes condensing to the cell center. PtdIns(4)P transiently localized to early phagosomes harboring wild-type or ΔicmT L. pneumophila and was cleared within minutes after uptake. During the following 2 h, PtdIns(4)P steadily accumulated only on wild-type LCVs, which maintained a discrete PtdIns(4)P identity spatially separated from calnexin-positive endoplasmic reticulum (ER) for at least 8 h. The separation of PtdIns(4)P-positive and ER membranes was even more pronounced for LCVs harboring ΔsidC-sdcA mutant bacteria defective for ER recruitment, without affecting initial bacterial replication in the pathogen vacuole. These findings elucidate the temporal and spatial dynamics of PI lipids implicated in LCV formation and provide insight into host cell membrane and effector protein interactions. American Society of Microbiology 2014-01-28 /pmc/articles/PMC3903275/ /pubmed/24473127 http://dx.doi.org/10.1128/mBio.00839-13 Text en Copyright © 2014 Weber et al. http://creativecommons.org/licenses/by-nc-sa/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-ShareAlike 3.0 Unported license (http://creativecommons.org/licenses/by-nc-sa/3.0/) , which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Weber, Stephen Wagner, Maria Hilbi, Hubert Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title | Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title_full | Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title_fullStr | Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title_full_unstemmed | Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title_short | Live-Cell Imaging of Phosphoinositide Dynamics and Membrane Architecture during Legionella Infection |
title_sort | live-cell imaging of phosphoinositide dynamics and membrane architecture during legionella infection |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903275/ https://www.ncbi.nlm.nih.gov/pubmed/24473127 http://dx.doi.org/10.1128/mBio.00839-13 |
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