The Mla pathway in Acinetobacter baumannii has no demonstrable role in anterograde lipid transport
Abstract
The asymmetric outer membrane (OM) of Gram-negative bacteria functions as a selective permeability barrier to the environment. Perturbations to OM lipid asymmetry sensitize the cell to antibiotics. As such, mechanisms involved in lipid asymmetry are fundamental to our understanding of OM lipid homeostasis. One such mechanism, the Maintenance of lipid asymmetry (Mla) pathway has been proposed to extract mislocalized glycerophospholipids from the outer leaflet of the OM and return them to the inner membrane (IM). Work on this pathway in Acinetobacter baumannii support conflicting models for the directionality of the Mla system being retrograde (OM to IM) or anterograde (IM to OM). Here we show conclusively that A. baumannii mla mutants exhibit no defects in anterograde transport. Furthermore, we identify an allele of the GTPase obgE that is synthetically sick in the absence of Mla; providing another link between cell envelope homeostasis and stringent response.
Data availability
Sequencing data (RNAseq) have been deposited to the database NCBI Gene Expression Omnibus. Accession number is GSE147139
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RNAseq of Mla mutantsNCBI Gene Expression Omnibus, GSE147139.
Article and author information
Author details
Funding
National Institute of Allergy and Infectious Diseases (AI129940)
- M Stephen Trent
National Institute of Allergy and Infectious Diseases (AI138576)
- M Stephen Trent
National Institute of Allergy and Infectious Diseases (AI150098)
- M Stephen Trent
National Science Foundation (049347-06)
- Matthew J Powers
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Powers et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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