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Gluconeogenic precursor availability regulates flux through the glyoxylate shunt in Pseudomonas aeruginosa.
J Biol Chem. 2018 09 14; 293(37):14260-14269.JB

Abstract

The glyoxylate shunt bypasses the oxidative decarboxylation steps of the tricarboxylic acid (TCA) cycle, thereby conserving carbon skeletons for gluconeogenesis and biomass production. In Escherichia coli, carbon flux is redirected through the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), following phosphorylation and inactivation of the TCA cycle enzyme, isocitrate dehydrogenase (ICD), by the kinase/phosphatase, AceK. In contrast, mycobacterial species lack AceK and employ a phosphorylation-insensitive isocitrate dehydrogenase (IDH), which is allosterically activated by the product of ICL activity, glyoxylate. However, Pseudomonas aeruginosa expresses IDH, ICD, ICL, and AceK, raising the question of how these enzymes are regulated to ensure proper flux distribution between the competing pathways. Here, we present the structure, kinetics, and regulation of ICL, IDH, and ICD from P. aeruginosa We found that flux partitioning is coordinated through reciprocal regulation of these enzymes, linking distribution of carbon flux to the availability of the key gluconeogenic precursors, oxaloacetate and pyruvate. Specifically, a greater abundance of these metabolites activated IDH and inhibited ICL, leading to increased TCA cycle flux. Regulation was also exerted through AceK-dependent phosphorylation of ICD; high levels of acetyl-CoA (which would be expected to accumulate when oxaloacetate is limiting) stimulated the kinase activity of AceK, whereas high levels of oxaloacetate stimulated its phosphatase activity. In summary, the TCA cycle-glyoxylate shunt branch point in P. aeruginosa has a complex enzymology that is profoundly different from those in other species characterized to date. Presumably, this reflects its predilection for consuming fatty acids, especially during infection scenarios.

Authors+Show Affiliations

From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom.From the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, United Kingdom mw240@cam.ac.uk.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30030382

Citation

Crousilles, Audrey, et al. "Gluconeogenic Precursor Availability Regulates Flux Through the Glyoxylate Shunt in Pseudomonas Aeruginosa." The Journal of Biological Chemistry, vol. 293, no. 37, 2018, pp. 14260-14269.
Crousilles A, Dolan SK, Brear P, et al. Gluconeogenic precursor availability regulates flux through the glyoxylate shunt in Pseudomonas aeruginosa. J Biol Chem. 2018;293(37):14260-14269.
Crousilles, A., Dolan, S. K., Brear, P., Chirgadze, D. Y., & Welch, M. (2018). Gluconeogenic precursor availability regulates flux through the glyoxylate shunt in Pseudomonas aeruginosa. The Journal of Biological Chemistry, 293(37), 14260-14269. https://doi.org/10.1074/jbc.RA118.004514
Crousilles A, et al. Gluconeogenic Precursor Availability Regulates Flux Through the Glyoxylate Shunt in Pseudomonas Aeruginosa. J Biol Chem. 2018 09 14;293(37):14260-14269. PubMed PMID: 30030382.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Gluconeogenic precursor availability regulates flux through the glyoxylate shunt in Pseudomonas aeruginosa. AU - Crousilles,Audrey, AU - Dolan,Stephen K, AU - Brear,Paul, AU - Chirgadze,Dimitri Y, AU - Welch,Martin, Y1 - 2018/07/20/ PY - 2018/06/19/received PY - 2018/07/18/revised PY - 2018/7/22/pubmed PY - 2019/4/10/medline PY - 2018/7/22/entrez KW - Pseudomonas aeruginosa KW - acetyl coenzyme A (acetyl-CoA) KW - allosteric regulation KW - bacterial metabolism KW - bacterial pathogenesis KW - bacterial virulence KW - enzyme regulation KW - enzyme structure KW - gluconeogenesis KW - glyoxylate shunt KW - isocitrate dehydrogenase KW - isocitrate lyase KW - metabolic adaptation KW - metabolic regulation KW - post-translational modification (PTM) KW - tricarboxylic acid cycle (TCA cycle) (Krebs cycle) SP - 14260 EP - 14269 JF - The Journal of biological chemistry JO - J Biol Chem VL - 293 IS - 37 N2 - The glyoxylate shunt bypasses the oxidative decarboxylation steps of the tricarboxylic acid (TCA) cycle, thereby conserving carbon skeletons for gluconeogenesis and biomass production. In Escherichia coli, carbon flux is redirected through the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), following phosphorylation and inactivation of the TCA cycle enzyme, isocitrate dehydrogenase (ICD), by the kinase/phosphatase, AceK. In contrast, mycobacterial species lack AceK and employ a phosphorylation-insensitive isocitrate dehydrogenase (IDH), which is allosterically activated by the product of ICL activity, glyoxylate. However, Pseudomonas aeruginosa expresses IDH, ICD, ICL, and AceK, raising the question of how these enzymes are regulated to ensure proper flux distribution between the competing pathways. Here, we present the structure, kinetics, and regulation of ICL, IDH, and ICD from P. aeruginosa We found that flux partitioning is coordinated through reciprocal regulation of these enzymes, linking distribution of carbon flux to the availability of the key gluconeogenic precursors, oxaloacetate and pyruvate. Specifically, a greater abundance of these metabolites activated IDH and inhibited ICL, leading to increased TCA cycle flux. Regulation was also exerted through AceK-dependent phosphorylation of ICD; high levels of acetyl-CoA (which would be expected to accumulate when oxaloacetate is limiting) stimulated the kinase activity of AceK, whereas high levels of oxaloacetate stimulated its phosphatase activity. In summary, the TCA cycle-glyoxylate shunt branch point in P. aeruginosa has a complex enzymology that is profoundly different from those in other species characterized to date. Presumably, this reflects its predilection for consuming fatty acids, especially during infection scenarios. SN - 1083-351X UR - https://www.unboundmedicine.com/medline/citation/30030382/Gluconeogenic_precursor_availability_regulates_flux_through_the_glyoxylate_shunt_in_Pseudomonas_aeruginosa_ L2 - https://linkinghub.elsevier.com/retrieve/pii/RA118.004514 DB - PRIME DP - Unbound Medicine ER -