Phosphatidylglycerol homeostasis in glycerol-phosphate auxotrophs of Staphylococcus aureus

BMC Microbiology

Research Article

Jiangwei Yao¹  Charles O Rock¹  Matthew Frank¹  Joshua B Parsons¹  Pamela Jackson¹ 

[1] Department of Infectious Diseases, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, 38105, Memphis, TN, USA;

关键词: Acyl carrier protein;    PlsY;    Acyl-phosphate;    Phosphatidylglycerol;    S. aureus;   

DOI  :  10.1186/1471-2180-13-260

 received in 2013-09-24, accepted in 2013-11-04,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe balanced synthesis of membrane phospholipids, fatty acids and cell wall constituents is a vital facet of bacterial physiology, but there is little known about the biochemical control points that coordinate these activities in Gram-positive bacteria. In Escherichia coli, the glycerol-phosphate acyltransferase (PlsB) plays a key role in coordinating fatty acid and phospholipid synthesis, but pathogens like Staphylococcus aureus have a different acyltransferase (PlsY), and the headgroup of the major membrane phospholipid, phosphatidylglycerol (PtdGro), is used as a precursor for lipoteichoic acid synthesis.ResultsThe PlsY acyltransferase in S. aureus was switched off by depriving strain PDJ28 (ΔgpsA) of the required glycerol supplement. Removal of glycerol from the growth medium led to the rapid cessation of phospholipid synthesis. However, the continued utilization of the headgroup caused a reduction in PtdGro coupled with the accumulation of CDP-diacylglycerol and phosphatidic acid. PtdGro was further decreased by its stimulated conversion to cardiolipin. Although acyl-acyl carrier protein (ACP) and malonyl-CoA accumulated, fatty acid synthesis continued at a reduced level leading to the intracellular accumulation of unusually long-chain free fatty acids.ConclusionsThe cessation of new phospholipid synthesis led to an imbalance in membrane compositional homeostasis. PtdGro biosynthesis was not coupled to headgroup turnover leading to the accumulation of pathway intermediates. The synthesis of cardiolipin significantly increased revealing a stress response to liberate glycerol-phosphate for PtdGro synthesis. Acyl-ACP accumulation correlated with a decrease in fatty acid synthesis; however, the coupling was not tight leading to the accumulation of intracellular fatty acids.

【 授权许可】

CC BY   
© Parsons et al.; licensee BioMed Central Ltd. 2013