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Genetic evidence for functional diversification of gram-negative intermembrane phospholipid transporters.
- Source :
-
PLoS genetics [PLoS Genet] 2024 Jun 24; Vol. 20 (6), pp. e1011335. Date of Electronic Publication: 2024 Jun 24 (Print Publication: 2024). - Publication Year :
- 2024
-
Abstract
- The outer membrane of gram-negative bacteria is a barrier to chemical and physical stress. Phospholipid transport between the inner and outer membranes has been an area of intense investigation and, in E. coli K-12, it has recently been shown to be mediated by YhdP, TamB, and YdbH, which are suggested to provide hydrophobic channels for phospholipid diffusion, with YhdP and TamB playing the major roles. However, YhdP and TamB have different phenotypes suggesting distinct functions. It remains unclear whether these functions are related to phospholipid metabolism. We investigated a synthetic cold sensitivity caused by deletion of fadR, a transcriptional regulator controlling fatty acid degradation and unsaturated fatty acid production, and yhdP, but not by ΔtamB ΔfadR or ΔydbH ΔfadR. Deletion of tamB recuses the ΔyhdP ΔfadR cold sensitivity further demonstrating the phenotype is related to functional diversification between these genes. The ΔyhdP ΔfadR strain shows a greater increase in cardiolipin upon transfer to the non-permissive temperature and genetically lowering cardiolipin levels can suppress cold sensitivity. These data also reveal a qualitative difference between cardiolipin synthases in E. coli, as deletion of clsA and clsC suppresses cold sensitivity but deletion of clsB does not. Moreover, increased fatty acid saturation is necessary for cold sensitivity and lowering this level genetically or through supplementation of oleic acid suppresses the cold sensitivity of the ΔyhdP ΔfadR strain. Together, our data clearly demonstrate that the diversification of function between YhdP and TamB is related to phospholipid metabolism. Although indirect regulatory effects are possible, we favor the parsimonious hypothesis that YhdP and TamB have differential phospholipid-substrate transport preferences. Thus, our data provide a potential mechanism for independent control of the phospholipid composition of the inner and outer membranes in response to changing conditions based on regulation of abundance or activity of YhdP and TamB.<br />Competing Interests: The authors have declared that no competing interests exist.<br /> (Copyright: © 2024 Rai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Subjects :
- Biological Transport genetics
Cardiolipins metabolism
Cardiolipins genetics
Escherichia coli genetics
Escherichia coli metabolism
Cold Temperature
Escherichia coli K12 genetics
Escherichia coli K12 metabolism
Gene Expression Regulation, Bacterial
Membrane Transport Proteins genetics
Membrane Transport Proteins metabolism
Fatty Acids metabolism
Phospholipid Transfer Proteins genetics
Phospholipid Transfer Proteins metabolism
Phospholipids metabolism
Phospholipids genetics
Escherichia coli Proteins genetics
Escherichia coli Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1553-7404
- Volume :
- 20
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- PLoS genetics
- Publication Type :
- Academic Journal
- Accession number :
- 38913742
- Full Text :
- https://doi.org/10.1371/journal.pgen.1011335