Indexed on: 06 May '20Published on: 06 May '20Published in: Journal of bacteriology
can utilize exogenous fatty acids for phospholipid synthesis. The fatty acid kinase FakA is essential for this utilization by phosphorylating exogenous fatty acids for incorporation into lipids. How FakA impacts the lipid membrane composition is unknown. Here, we used mass spectrometry to determine the membrane lipid composition and properties of in the absence of We found the mutant to have increased abundance of lipids containing longer acyl-chains. Since does not synthesize unsaturated fatty acids, we utilized oleic acid (18:1) to track exogenous fatty acid incorporation into lipids. We observed a concentration-dependent incorporation of exogenous fatty acids into the membrane that required FakA. We also tested how FakA and exogenous fatty acids impact membrane-related physiology and identified changes in membrane potential, cellular respiration, and membrane fluidity. To mimic the host environment, we characterized the lipid composition of wild-type and mutant bacteria grown in mouse skin homogenate. We show that wild-type can incorporate exogenous unsaturated fatty acids from host tissue highlighting the importance of FakA in the presence of host skin tissue. In conclusion, FakA is important for maintaining the composition and properties of the phospholipid membrane in the presence of exogenous fatty acids, impacting overall cell physiology. Environmental fatty acids can be harvested to supplement endogenous fatty acid synthesis to produce membranes and circumvent fatty acid biosynthesis inhibitors. However, how the inability to use these fatty acids impacts lipids is unclear. Our results reveal lipid composition changes in response to fatty acid addition and when is unable to activate fatty acids through FakA. We identify concentration-dependent utilization of oleic acid, that when combined with previous work, provides evidence that fatty acids can serve as a signal to Furthermore, using mouse skin homogenates as a surrogate for conditions, we show that can incorporate host fatty acids. This study highlights how exogenous fatty acids impact bacterial membrane composition and function. Copyright © 2020 American Society for Microbiology.