Mechanistic diversity and regulation of Type II fatty acid synthesis

2002 ◽  
Vol 30 (6) ◽  
pp. 1050-1055 ◽  
Author(s):  
H. Marrakchi ◽  
Y.-M. Zhang ◽  
C. O. Rock

Fatty acid biosynthesis is catalysed in most bacteria by a group of highly conserved proteins known as the Type II fatty acid synthase (FAS) system. The Type II system organization is distinct from its mammalian counterpart and offers several unique sites for selective inhibition by antibacterial agents. There has been remarkable progress in the understanding of the genetics, biochemistry and regulation of Type II FASs. One important advance is the discovery of the interaction between the fatty acid degradation regulator, FadR, and the fatty acid biosynthesis regulator, FabR, in the transcriptional control of unsaturated fatty acid synthesis in Escherichia coli. The availability of genomic sequences and high-resolution protein crystal structures has expanded our understanding of Type II FASs beyond the E. coli model system to a number of pathogens. The molecular diversity among the pathway enzymes is illustrated by the discovery of a new type of enoyl-reductase in Streptococcus pneumoniae [enoyl-acyl carrier protein (ACP) reductase II, FabK], the presence of two enoyl-reductases in Bacillus subtilis (enoyl-ACP reductases I and III, FabI and FabL), and the use of a new mechanism for unsaturated fatty acid formation in S. pneumoniae (trans-2-cis-3-enoyl-ACP isomerase, FabM). The solution structure of ACP from Mycobacterium tuberculosis revealed features common to all ACPs, but its extended C-terminal domain may reflect a specific interaction with very-long-chain intermediates.

1991 ◽  
Vol 260 (6) ◽  
pp. L577-L585 ◽  
Author(s):  
J. Rami ◽  
S. M. Sasic ◽  
S. A. Rooney

Silica instillation causes lung surfactant accumulation as well as hyperplasia and hypertrophy of type II pneumocytes. Two populations of type II cells can be isolated from silica-treated rats: type IIA, which are similar to type II cells from normal animals and type IIB, which are larger and have a higher rate of phosphatidylcholine biosynthesis. We have compared fatty acid biosynthesis and phosphatidylcholine secretion in types IIA and IIB cells and in type II cells from control rats. The cells were isolated by elastase digestion and panning on immunoglobulin G-coated plates and fractionated into types IIA and IIB by centrifugal elutriation. Type IIB cells contained more phospholipid and had an enhanced rate of [3H]choline incorporation into phosphatidylcholine. The activity of choline-phosphate cytidylyltransferase was elevated in the type IIB cells and the extent of the increase was diminished when phosphatidylglycerol was included in the assay, suggesting that the enhanced activity was due to enzyme activation rather than protein synthesis. The basal rate of phosphatidylcholine secretion was the same in all three groups as was the response to a variety of secretagogues. Incorporation of [3H]acetate into fatty acids was elevated in type IIB cells and the activity of fatty acid synthase was eightfold greater than in control cells. These data show that de novo fatty acid biosynthesis is increased in hypertrophic type II cells and that surfactant secretion is not elevated.


2003 ◽  
Vol 47 (1) ◽  
pp. 297-301 ◽  
Author(s):  
Ross F. Waller ◽  
Stuart A. Ralph ◽  
Michael B. Reed ◽  
Vanessa Su ◽  
James D. Douglas ◽  
...  

ABSTRACT It has long been held that the malaria parasite, Plasmodium sp., is incapable of de novo fatty acid synthesis. This view has recently been overturned with the emergence of data for the presence of a fatty acid biosynthetic pathway in the relict plastid of P. falciparum (known as the apicoplast). This pathway represents the type II pathway common to plant chloroplasts and bacteria but distinct from the type I pathway of animals including humans. Specific inhibitors of the type II pathway, thiolactomycin and triclosan, have been reported to target this Plasmodium pathway. Here we report further inhibitors of the plastid-based pathway that inhibit Plasmodium parasites. These include several analogues of thiolactomycin, two with sixfold-greater efficacy than thiolactomycin. We also report that parasites respond very rapidly to such inhibitors and that the greatest sensitivity is seen in ring-stage parasites. This study substantiates the importance of fatty acid synthesis for blood-stage parasite survival and shows that this pathway provides scope for the development of novel antimalarial drugs.


1980 ◽  
Vol 186 (3) ◽  
pp. 937-944 ◽  
Author(s):  
P A Sinnett-Smith ◽  
R G Vernon ◽  
R J Mayer

1. The specific activities of fatty acid synthetase, acetyl-CoA carboxylase and pyruvate dehydrogenase were measured in rat adipose-tissue extracts in pregnancy and lactation. Fatty acid synthetase specific activity correlates very closely with the rate of fatty acid synthesis, the enzyme specific activity decreasing after mid-pregnancy in a manner very similar to the rate of fatty acid synthesis. Acetyl-CoA carboxylase specific activity also decreases dramatically after mid-pregnancy. Initial pyruvate dehydrogenase specific activity shows a decrease between 2 days pre partum and 2 days post partum, but total enzyme activity shows no significant change in the same period. 2. Immunotitrations of fatty acid synthetase and pyruvate dehydrogenase activities were carried out; the titrations showed that the change in the fatty acid synthetase activity is due to a change in the enzyme amount; the amount of pyruvate dyhydrogenase does not change. Therefore the decrease in fatty acid biosynthesis in subcutaneous and parametrial adipose tissue in late pregnancy and early lactation is associated with a decrease in the amount of at least one of the enzymes involved in fatty acid biosynthesis. The correlation of these events with known hormonal changes is discussed.


2008 ◽  
Vol 74 (16) ◽  
pp. 5078-5085 ◽  
Author(s):  
Aner Gurvitz ◽  
J. Kalervo Hiltunen ◽  
Alexander J. Kastaniotis

ABSTRACT We describe the physiological function of heterologously expressed Mycobacterium tuberculosis InhA during de novo lipoic acid synthesis in yeast (Saccharomyces cerevisiae) mitochondria. InhA, representing 2-trans-enoyl-acyl carrier protein reductase and the target for the front-line antituberculous drug isoniazid, is involved in the activity of dissociative type 2 fatty acid synthase (FASII) that extends associative type 1 fatty acid synthase (FASI)-derived C20 fatty acids to form C60-to-C90 mycolic acids. Mycolic acids are major constituents of the protective layer around the pathogen that contribute to virulence and resistance to certain antimicrobials. Unlike FASI, FASII is thought to be incapable of de novo biosynthesis of fatty acids. Here, the genes for InhA (Rv1484) and four similar proteins (Rv0927c, Rv3485c, Rv3530c, and Rv3559c) were expressed in S. cerevisiae etr1Δ cells lacking mitochondrial 2-trans-enoyl-thioester reductase activity. The phenotype of the yeast mutants includes the inability to produce sufficient levels of lipoic acid, form mitochondrial cytochromes, respire, or grow on nonfermentable carbon sources. Yeast etr1Δ cells expressing mitochondrial InhA were able to respire, grow on glycerol, and produce lipoic acid. Commensurate with a role in mitochondrial de novo fatty acid biosynthesis, InhA could accept in vivo much shorter acyl-thioesters (C4 to C8) than was previously thought (>C12). Moreover, InhA functioned in the absence of AcpM or protein-protein interactions with its native FASII partners KasA, KasB, FabD, and FabH. None of the four proteins similar to InhA complemented the yeast mutant phenotype. We discuss the implications of our findings with reference to lipoic acid synthesis in M. tuberculosis and the potential use of yeast FASII mutants for investigating the physiological function of drug-targeted pathogen enzymes involved in fatty acid biosynthesis.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Fan Hu ◽  
April L. Clevenger ◽  
Peng Zheng ◽  
Qiongye Huang ◽  
Zhaokai Wang

Abstract Background Schizochytrium species are known for their abundant production of docosahexaenoic acid (DHA). Low temperatures can promote the biosynthesis of polyunsaturated fatty acids (PUFAs) in many species. This study investigates low-temperature effects on DHA biosynthesis in Schizochytrium sp. TIO01 and its underlying mechanism. Results The Schizochytrium fatty acid biosynthesis pathway was evaluated based on de novo genome assembly (contig N50 = 2.86 Mb) and iTRAQ-based protein identification. Our findings revealed that desaturases, involved in DHA synthesis via the fatty acid synthase (FAS) pathway, were completely absent. The polyketide synthase (PKS) pathway and the FAS pathway are, respectively, responsible for DHA and saturated fatty acid synthesis in Schizochytrium. Analysis of fatty acid composition profiles indicates that low temperature has a significant impact on the production of DHA in Schizochytrium, increasing the DHA content from 43 to 65% of total fatty acids. However, the expression levels of PKS pathway genes were not significantly regulated as the DHA content increased. Further, gene expression analysis showed that pathways related to the production of substrates (acetyl-CoA and NADPH) for fatty acid synthesis (the branched-chain amino acid degradation pathway and the pentose phosphate pathway) and genes related to saturated fatty acid biosynthesis (the FAS pathway genes and malic enzyme) were, respectively, upregulated and downregulated. These results indicate that low temperatures increase the DHA content by likely promoting the entry of relatively large amounts of substrates into the PKS pathway. Conclusions In this study, we provide genomic, proteomic, and transcriptomic evidence for the fatty acid synthesis pathway in Schizochytrium and propose a mechanism by which low temperatures promote the accumulation of DHA in Schizochytrium. The high-quality and nearly complete genome sequence of Schizochytrium provides a valuable reference for investigating the regulation of polyunsaturated fatty acid biosynthesis and the evolutionary characteristics of Thraustochytriidae species.


2021 ◽  
Author(s):  
Bohan Ma ◽  
Yue Li ◽  
Mohamed Khalifa ◽  
Meng Teng ◽  
Aijing Zhang ◽  
...  

Abstract Background: Long non-coding RNAs (lncRNAs) are non-coding RNAs of more than 200 nucleotides. To date, the roles of lncRNAs in soybean fatty acid synthesis have not been fully studied. Here, the low-linolenic acid ‘mutant 72’ (MT72) and the wild-type control ‘JiNong 18’(JN18) were used. Based on the previously published data on lncRNAs related RNA-seq in young pods of soybean 30 d to 40 d after flowering, lncRNAs and mRNAs from soybean pods 50 d after flowering were identified using high-throughput sequencing. The possible target genes of lncRNAs were predicted, and the functions related to fatty acid synthesis were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).Results: A total of 10,500 lncRNAs and 54,370 mRNAs were identified, and 115 possible target genes of 1,805 differentially expressed lncRNAs were found to be involved in fatty acid synthesis. A network of lncRNAs and mRNAs was constructed, and a total of 604 lncRNAs and 1,484 mRNAs had regulatory relationships. Among them, 115 target genes of 77 lncRNAs were directly or indirectly involved in fatty acid biosynthesis.Conclusions: The function related to fatty acid synthesis was predicted by differential expression of the target gene mRNAs interacting with lncRNAs. In conclusion, our results provide a theoretical basis for studies on fatty acid synthesis of lncRNAs in soybean.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 706
Author(s):  
Antonio J. Moreno-Pérez ◽  
Raquel Martins-Noguerol ◽  
Cristina DeAndrés-Gil ◽  
Mónica Venegas-Calerón ◽  
Rosario Sánchez ◽  
...  

Histone modifications are of paramount importance during plant development. Investigating chromatin remodeling in developing oilseeds sheds light on the molecular mechanisms controlling fatty acid metabolism and facilitates the identification of new functional regions in oil crop genomes. The present study characterizes the epigenetic modifications H3K4me3 in relationship with the expression of fatty acid-related genes and transcription factors in developing sunflower seeds. Two master transcriptional regulators identified in this analysis, VIV1 (homologous to Arabidopsis ABI3) and FUS3, cooperate in the regulation of WRINKLED 1, a transcriptional factor regulating glycolysis, and fatty acid synthesis in developing oilseeds.


2021 ◽  
Vol 22 (11) ◽  
pp. 5951
Author(s):  
Xiaofei Zhou ◽  
Xiaoyu Ling ◽  
Huijuan Guo ◽  
Keyan Zhu-Salzman ◽  
Feng Ge ◽  
...  

Bacterial symbionts associated with insects are often involved in host development and ecological adaptation. Serratia symbiotica, a common facultative endosymbiont harbored in pea aphids, improves host fitness and heat tolerance, but studies concerning the nutritional metabolism and impact on the aphid host associated with carrying Serratia are limited. In the current study, we showed that Serratia-infected aphids had a shorter nymphal developmental time and higher body weight than Serratia-free aphids when fed on detached leaves. Genes connecting to fatty acid biosynthesis and elongation were up-regulated in Serratia-infected aphids. Specifically, elevated expression of fatty acid synthase 1 (FASN1) and diacylglycerol-o-acyltransferase 2 (DGAT2) could result in accumulation of myristic acid, palmitic acid, linoleic acid, and arachidic acid in fat bodies. Impairing fatty acid synthesis in Serratia-infected pea aphids either by a pharmacological inhibitor or through silencing FASN1 and DGAT2 expression prolonged the nymphal growth period and decreased the aphid body weight. Conversely, supplementation of myristic acid (C14:0) to these aphids restored their normal development and weight gain. Our results indicated that Serratia promoted development and growth of its aphid host through enhancing fatty acid biosynthesis. Our discovery has shed more light on nutritional effects underlying the symbiosis between aphids and facultative endosymbionts.


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