Extending the story of very-long-chain fatty acid elongation.
Very-long-chain fatty acids (VLCFAs) are essential molecules produced by all plant cells, and are components or precursors of numerous specialized metabolites synthesized in specific cell types. VLCFAs are elongated by an endoplasmic reticulum-localized fatty acid elongation complex of four core enzymes, which sequentially add two carbon units to a growing acyl chain. Identification and characterization of these enzymes in Arabidopsis thaliana has revealed that three of the four enzymes act as generalists, contributing to all metabolic pathways that require VLCFAs. A fourth component, the condensing enzyme, provides substrate specificity and determines the amount of product synthesized by the entire complex. Land plants have two families of condensing enzymes, FATTY ACID ELONGATION 1 (FAE1)-type ketoacyl-CoA synthases (KCSs) and ELONGATION DEFECTIVE-LIKEs (ELO-LIKEs). Our current knowledge of the specific roles of different condensing enzymes is incomplete, as is our understanding of the biological function of a recently characterized family of proteins, CER2-LIKEs, which contribute to condensing enzyme function. More broadly, the stoichiometry and quaternary structure of the fatty acid elongase complex remains poorly understood, and specific phylogenetic and biochemical questions persist for each component of the complex. Investigation of VLCFA elongation in different organisms, structural biochemistry, and cell biology approaches stand to greatly benefit this field of plant biology.
['Haslam|Tegan M|TM|', 'Kunst|Ljerka|L|']
D000123:Acetyltransferases D017360:Arabidopsis D019669:Embryophyta D004721:Endoplasmic Reticulum D000081031:Fatty Acid Elongases D005227:Fatty Acids D008958:Models, Molecular D009097:Multienzyme Complexes D010940:Plant Proteins D013379:Substrate Specificity
Very-long-chain fatty acid Very-long-chain fatty acid VLCFA Arabidopsis thaliana Condensing enzymes KETOACYL-COA SYNTHASE CER2-LIKEs Fatty acid elongase complex ACP CER2 CoA ECERIFERUM2 ECR ELO ELONGATION DEFECTIVE ENOYL-COA REDUCTASE HCD HYDROXYACYL-COA DEHYDRATASE KCR KCS KETOACYL-COA REDUCTASE LACS LONG-CHAIN ACYL-COENZYME A SYNTHETASE acyl carrier protein coenzyme A very-long-chain fatty acid