Polar targeting and assembly of the Legionella Dot/Icm type IV secretion system (T4SS) by T6SS-related components
Abstract
Legionella pneumophila, the causative agent of Legionnaires′ disease, survives and replicates inside amoebae and macrophages by injecting a large number of protein effectors into the host cells′ cytoplasm via the Dot/Icm type IVB secretion system (T4BSS). Previously, we showed that the Dot/Icm T4BSS is localized to both poles of the bacterium and that polar secretion is necessary for the proper targeting of the Legionella containing vacuole (LCV). Here we show that polar targeting of the Dot/Icm core-transmembrane subcomplex (DotC, DotD, DotF, DotG and DotH) is mediated by two Dot/Icm proteins, DotU and IcmF, which are able to localize to the poles of L. pneumophila by themselves. Interestingly, DotU and IcmF are homologs of the T6SS components TssL and TssM, which are part of the T6SS membrane complex (MC). We propose that Legionella co-opted these T6SS components to a novel function that mediates subcellular localization and assembly of this T4SS. Finally, in depth examination of the biogenesis pathway revealed that polar targeting and assembly of the Legionella T4BSS apparatus is mediated by an innovative ″outside-inside″ mechanism.
Additional Information
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. bioRxiv preprint first posted online May. 7, 2018. We thank Dr. Ralph Isberg (Tuft's University) for antibodies that recognize DotF and DotH, Ms. Emily Buford for technical assistance and Dr. Petra Levin (Washington University) for assistance with deconvolution microscopy. We also recognize Dr. Eep Darwin for key suggestions and critical appraisal of this manuscript. This work was funded by NIH grant AI48052 to J.P.V.Attached Files
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Additional details
- Eprint ID
- 90523
- Resolver ID
- CaltechAUTHORS:20181030-144940113
- AI48052
- NIH
- Created
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2018-10-30Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field