Revisiting the coupling of fatty acid to phospholipid synthesis in bacteria with FapR regulation

• DOI: 10.1111/mmi.14574
• Publication Date: 2020-07-16T08:40:02Z
• Authors: Federico Machinan...; Leandro Nakamatsu; Gustavo E. Schujman; Diego de Mendoza; Daniela Albanesi
• Keywords: GRAM-POSITIVE BACTERIA; FOS: Mechanical engineering; Protein Synthesis; Regulon; Biochemistry; Microbiology; 03 medical and health sciences; Engineering; Bacterial Proteins; https://purl.org/becyt/ford/1.6; Biochemistry, Genetics and Molecular Biology; Acyl Carrier Protein; Genetics; Coupling (piping); RNA Sequencing Data Analysis; https://purl.org/becyt/ford/1; Ribosome Structure and Translation Mechanisms; ACYL-ACP; PLSX; Molecular Biology; Biology; Phospholipids; FATTY ACID KINASE; 0303 health sciences; Bacteria; Lipogenesis; Fatty Acids; Membrane; Bacterial Physiology and Genetics; Life Sciences; ACETYL-COA CARBOXYLASE; MEMBRANE BIOGENESIS REGULATION; Fatty acid; Mechanical engineering; Phospholipid; FOS: Biological sciences; Bacillus subtilis

AbstractA key aspect in membrane biogenesis is the coordination of fatty acid to phospholipid synthesis rates. In most bacteria, PlsX is the first enzyme of the phosphatidic acid synthesis pathway, the common precursor of all phospholipids. Previously, we proposed that PlsX is a key regulatory point that synchronizes the fatty acid synthase II with phospholipid synthesis in Bacillus subtilis. However, understanding the basis of such coordination mechanism remained a challenge in Gram‐positive bacteria. Here, we show that the inhibition of fatty acid and phospholipid synthesis caused by PlsX depletion leads to the accumulation of long‐chain acyl‐ACPs, the end products of the fatty acid synthase II. Hydrolysis of the acyl‐ACP pool by heterologous expression of a cytosolic thioesterase relieves the inhibition of fatty acid synthesis, indicating that acyl‐ACPs are feedback inhibitors of this metabolic route. Unexpectedly, inactivation of PlsX triggers a large increase of malonyl‐CoA leading to induction of the fap regulon. This finding discards the hypothesis, proposed for B. subtilis and extended to other Gram‐positive bacteria, that acyl‐ACPs are feedback inhibitors of the acetyl‐CoA carboxylase. Finally, we propose that the continuous production of malonyl‐CoA during phospholipid synthesis inhibition provides an additional mechanism for fine‐tuning the coupling between phospholipid and fatty acid production in bacteria with FapR regulation.