scholarly journals Phosphatidylinositol synthesis, its selective salvage, and inter-regulation of anionic phospholipids in Toxoplasma gondii

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Bingjian Ren ◽  
Pengfei Kong ◽  
Fatima Hedar ◽  
Jos F. Brouwers ◽  
Nishith Gupta
Keyword(s):  
Toxoplasma Gondii ◽  
Isotope Labeling ◽  
De Novo ◽  
Lipid Synthesis ◽  
Gliding Motility ◽  
Lytic Cycle ◽  
Metabolic Demand ◽  
Anionic Phospholipids ◽  
Lipid Species ◽  
Strategic Allocation

AbstractPhosphatidylinositol (PtdIns) serves as an integral component of eukaryotic membranes; however, its biosynthesis in apicomplexan parasites remains poorly understood. Here we show that Toxoplasma gondii—a common intracellular pathogen of humans and animals—can import and co-utilize myo-inositol with the endogenous CDP-diacylglycerol to synthesize PtdIns. Equally, the parasite harbors a functional PtdIns synthase (PIS) containing a catalytically-vital CDP-diacylglycerol phosphotransferase motif in the Golgi apparatus. Auxin-induced depletion of PIS abrogated the lytic cycle of T. gondii in human cells due to defects in cell division, gliding motility, invasion, and egress. Isotope labeling of the PIS mutant in conjunction with lipidomics demonstrated de novo synthesis of specific PtdIns species, while revealing the salvage of other lipid species from the host cell. Not least, the mutant showed decline in phosphatidylthreonine, and elevation of selected phosphatidylserine and phosphatidylglycerol species, indicating a rerouting of CDP-diacylglycerol and homeostatic inter-regulation of anionic phospholipids upon knockdown of PIS. In conclusion, strategic allocation of own and host-derived PtdIns species to gratify its metabolic demand features as a notable adaptive trait of T. gondii. Conceivably, the dependence of T. gondii on de novo lipid synthesis and scavenging can be exploited to develop new anti-infectives.

scholarly journals Toxoplasma gondii acetyl-CoA synthetase is involved in fatty acid elongation (of long fatty acid chains) during tachyzoite life stages

2018 ◽  
Vol 59 (6) ◽  
pp. 994-1004 ◽  
Author(s):  
David Dubois ◽  
Stella Fernandes ◽  
Souad Amiar ◽  
Sheena Dass ◽  
Nicholas J. Katris ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Toxoplasma Gondii ◽  
Isotope Labeling ◽  
De Novo ◽  
Lipid Synthesis ◽  
Minor Effect ◽  
Parasite Line ◽  
Acetyl Coa ◽  
Apicomplexan Parasites ◽  
A Minor

Apicomplexan parasites are pathogens responsible for major human diseases such as toxoplasmosis caused by Toxoplasma gondii and malaria caused by Plasmodium spp. Throughout their intracellular division cycle, the parasites require vast and specific amounts of lipids to divide and survive. This demand for lipids relies on a fine balance between de novo synthesized lipids and scavenged lipids from the host. Acetyl-CoA is a major and central precursor for many metabolic pathways, especially for lipid biosynthesis. T. gondii possesses a single cytosolic acetyl-CoA synthetase (TgACS). Its role in the parasite lipid synthesis is unclear. Here, we generated an inducible TgACS KO parasite line and confirmed the cytosolic localization of the protein. We conducted 13C-stable isotope labeling combined with mass spectrometry-based lipidomic analyses to unravel its putative role in the parasite lipid synthesis pathway. We show that its disruption has a minor effect on the global FA composition due to the metabolic changes induced to compensate for its loss. However, we could demonstrate that TgACS is involved in providing acetyl-CoA for the essential fatty elongation pathway to generate FAs used for membrane biogenesis. This work provides novel metabolic insight to decipher the complex lipid synthesis in T. gondii.

scholarly journals Molecular Characterization of Toxoplasma gondii Formin 3, an Actin Nucleator Dispensable for Tachyzoite Growth and Motility

2011 ◽  
Vol 11 (3) ◽  
pp. 343-352 ◽  
Author(s):  
Wassim Daher ◽  
Natacha Klages ◽  
Marie-France Carlier ◽  
Dominique Soldati-Favre
Keyword(s):  
Toxoplasma Gondii ◽  
Actin Polymerization ◽  
Life Stage ◽  
Gliding Motility ◽  
Lytic Cycle ◽  
Host Cells ◽  
Content Type ◽  
Parasite Motility ◽  
Actin Nucleator

ABSTRACT Toxoplasma gondii belongs to the phylum Apicomplexa, a group of obligate intracellular parasites that rely on gliding motility to enter host cells. Drugs interfering with the actin cytoskeleton block parasite motility, host cell invasion, and egress from infected cells. Myosin A, profilin, formin 1, formin 2, and actin-depolymerizing factor have all been implicated in parasite motility, yet little is known regarding the importance of actin polymerization and other myosins for the remaining steps of the parasite lytic cycle. Here we establish that T. gondii formin 3 (TgFRM3), a newly described formin homology 2 domain (FH2)-containing protein, binds to Toxoplasma actin and nucleates rabbit actin assembly in vitro . TgFRM3 expressed as a transgene exhibits a patchy localization at several distinct structures within the parasite. Disruption of the TgFRM3 gene by double homologous recombination in a ku80-ko strain reveals no vital function for tachyzoite propagation in vitro , which is consistent with its weak level of expression in this life stage. Conditional stabilization of truncated forms of TgFRM3 suggests that different regions of the molecule contribute to distinct localizations. Moreover, expression of TgFRM3 lacking the C-terminal domain severely affects parasite growth and replication. This work provides a first insight into how this specialized formin, restricted to the group of coccidia, completes its actin-nucleating activity.

scholarly journals Toxoplasma gondii acyl-lipid metabolism: de novo synthesis from apicoplast-generated fatty acids versus scavenging of host cell precursors

2006 ◽  
Vol 394 (1) ◽  
pp. 197-205 ◽  
Author(s):  
Cordelia Bisanz ◽  
Olivier Bastien ◽  
Delphine Grando ◽  
Juliette Jouhet ◽  
Eric Maréchal ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Toxoplasma Gondii ◽  
Host Cell ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Acyl Carrier Protein ◽  
Lipid Synthesis ◽  
Yeast Cells ◽  
Secondary Endosymbiosis ◽  
Acyl Lipid

Toxoplasma gondii is an obligate intracellular parasite that contains a relic plastid, called the apicoplast, deriving from a secondary endosymbiosis with an ancestral alga. Metabolic labelling experiments using [14C]acetate led to a substantial production of numerous glycero- and sphingo-lipid classes in extracellular tachyzoites. Syntheses of all these lipids were affected by the herbicide haloxyfop, demonstrating that their de novo syntheses necessarily required a functional apicoplast fatty acid synthase II. The complex metabolic profiles obtained and a census of glycerolipid metabolism gene candidates indicate that synthesis is probably scattered in the apicoplast membranes [possibly for PA (phosphatidic acid), DGDG (digalactosyldiacylglycerol) and PG (phosphatidylglycerol)], the endoplasmic reticulum (for major phospholipid classes and ceramides) and mitochondria (for PA, PG and cardiolipid). Based on a bioinformatic analysis, it is proposed that apicoplast produced acyl-ACP (where ACP is acyl-carrier protein) is transferred to glycerol-3-phosphate for apicoplast glycerolipid synthesis. Acyl-ACP is also probably transported outside the apicoplast stroma and irreversibly converted into acyl-CoA. In the endoplasmic reticulum, acyl-CoA may not be transferred to a three-carbon backbone by an enzyme similar to the cytosolic plant glycerol-3-phosphate acyltransferase, but rather by a dual glycerol-3-phosphate/dihydroxyacetone-3-phosphate acyltransferase like in animal and yeast cells. We further showed that intracellular parasites could also synthesize most of their lipids from scavenged host cell precursors. The observed appearance of glycerolipids specific to either the de novo pathway in extracellular parasites (unknown glycerolipid 1 and the plant like DGDG), or the intracellular stages (unknown glycerolipid 8), may explain the necessary coexistence of both de novo parasitic acyl-lipid synthesis and recycling of host cell compounds.

Lipid metabolism in the embryos of diabetic rats during early organogenesis: modulatory effect of prostaglandin E2

2003 ◽  
Vol 15 (1) ◽  
pp. 75 ◽  
Author(s):  
Debora Sinner ◽  
J. Matías Caviglia ◽  
Alicia Jawerbaum ◽  
R. Ariel Igal ◽  
Elida Gonzalez
Keyword(s):  
Lipid Metabolism ◽  
Prostaglandin E2 ◽  
Lipid Profile ◽  
De Novo ◽  
Lipid Synthesis ◽  
Diabetic Rats ◽  
Lipid Classes ◽  
De Novo Synthesis ◽  
Lipid Species ◽  
Early Organogenesis

The purpose of this work was to evaluate de novo lipid biosynthesis and the lipid profile, and to study the effect of prostaglandin E2 (PGE2; prostaglandin has previously been found to be involved in diabetes embryopathy) on lipid metabolism in embryos from control and streptozotocin-induced diabetic rats during organogenesis. Increased levels of triacylglycerols were found in embryos of diabetic rats compared with controls, whereas no differences were detected in the levels of cholesterol, cholesterylester, phosphatidylcholine and phosphatidylethanolamine. When the de novo synthesis of lipids in the embryo was studied using [14C]acetate as a tracer, a diminished rate of incorporation of [14C]acetate into the evaluated lipid classes was detected in the diabetic embryo compared with controls. Addition of PGE2 did not modify the incorporation of [14C]acetate into any of the lipid species of control embryos, but enhanced the incorporation of [14C]acetate into triacylglycerol, cholesterylesters, phosphatidylcholine and phosphatidylethanolamine of embryos from diabetic rats. The study’s results show alterations in both synthesis and concentrations of lipids in the embryos of diabetic rats. Interestingly, the results demonstrate that the addition of PGE2, a prostaglandin that reverses the embryonic morphological abnormalities induced by diabetes, prevents disturbances in embryo lipid synthesis caused by diabetes.

scholarly journals Calcium-dependent phosphorylation alters class XIVa myosin function in the protozoan parasite Toxoplasma gondii

2014 ◽  
Vol 25 (17) ◽  
pp. 2579-2591 ◽  
Author(s):  
Qing Tang ◽  
Nicole Andenmatten ◽  
Miryam A. Hortua Triana ◽  
Bin Deng ◽  
Markus Meissner ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Calcium Ionophore ◽  
Protozoan Parasite ◽  
Gliding Motility ◽  
Lytic Cycle ◽  
Host Cells ◽  
Response To Treatment ◽  
Apicomplexan Parasites ◽  
Calcium Dependent

Class XIVa myosins comprise a unique group of myosin motor proteins found in apicomplexan parasites, including those that cause malaria and toxoplasmosis. The founding member of the class XIVa family, Toxoplasma gondii myosin A (TgMyoA), is a monomeric unconventional myosin that functions at the parasite periphery to control gliding motility, host cell invasion, and host cell egress. How the motor activity of TgMyoA is regulated during these critical steps in the parasite's lytic cycle is unknown. We show here that a small-molecule enhancer of T. gondii motility and invasion (compound 130038) causes an increase in parasite intracellular calcium levels, leading to a calcium-dependent increase in TgMyoA phosphorylation. Mutation of the major sites of phosphorylation altered parasite motile behavior upon compound 130038 treatment, and parasites expressing a nonphosphorylatable mutant myosin egressed from host cells more slowly in response to treatment with calcium ionophore. These data demonstrate that TgMyoA undergoes calcium-dependent phosphorylation, which modulates myosin-driven processes in this important human pathogen.

scholarly journals Toxoplasma LIPIN is essential in channeling host lipid fluxes through membrane biogenesis and lipid storage

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sheena Dass ◽  
Serena Shunmugam ◽  
Laurence Berry ◽  
Christophe-Sebastien Arnold ◽  
Nicholas J. Katris ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
De Novo ◽  
Lipid Synthesis ◽  
Parasite Development ◽  
Membrane Biogenesis ◽  
Membrane Phospholipids ◽  
Phosphatidic Acid Phosphatase ◽  
Intracellular Parasites ◽  
Parasite Survival

AbstractApicomplexa are obligate intracellular parasites responsible for major human diseases. Their intracellular survival relies on intense lipid synthesis, which fuels membrane biogenesis. Parasite lipids are generated as an essential combination of fatty acids scavenged from the host and de novo synthesized within the parasite apicoplast. The molecular and metabolic mechanisms allowing regulation and channeling of these fatty acid fluxes for intracellular parasite survival are currently unknown. Here, we identify an essential phosphatidic acid phosphatase in Toxoplasma gondii, TgLIPIN, as the central metabolic nexus responsible for controlled lipid synthesis sustaining parasite development. Lipidomics reveal that TgLIPIN controls the synthesis of diacylglycerol and levels of phosphatidic acid that regulates the fine balance of lipids between storage and membrane biogenesis. Using fluxomic approaches, we uncover the first parasite host-scavenged lipidome and show that TgLIPIN prevents parasite death by ‘lipotoxicity’ through effective channeling of host-scavenged fatty acids to storage triacylglycerols and membrane phospholipids.

scholarly journals Lipid Acyl Chain Remodeling in Yeast

2015 ◽  
Vol 8s1 ◽  
pp. LPI.S31780 ◽  
Author(s):  
Mike F. Renne ◽  
Xue Bao ◽  
Cedric H. De Smet ◽  
Anton I. P. M. De Kroon
Keyword(s):  
Intracellular Transport ◽  
De Novo ◽  
Acyl Chain ◽  
Model Organism ◽  
Lipid Synthesis ◽  
Membrane Lipid ◽  
Lipid Homeostasis ◽  
Synthetic Process ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

Membrane lipid homeostasis is maintained by de novo synthesis, intracellular transport, remodeling, and degradation of lipid molecules. Glycerophospholipids, the most abundant structural component of eukaryotic membranes, are subject to acyl chain remodeling, which is defined as the post-synthetic process in which one or both acyl chains are exchanged. Here, we review studies addressing acyl chain remodeling of membrane glycerophospholipids in Saccharomyces cerevisiae, a model organism that has been successfully used to investigate lipid synthesis and its regulation. Experimental evidence for the occurrence of phospholipid acyl chain exchange in cardiolipin, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine is summarized, including methods and tools that have been used for detecting remodeling. Progress in the identification of the enzymes involved is reported, and putative functions of acyl chain remodeling in yeast are discussed.

scholarly journals Snf1 Is a Regulator of Lipid Accumulation in Yarrowia lipolytica

2013 ◽  
Vol 79 (23) ◽  
pp. 7360-7370 ◽  
Author(s):  
John Seip ◽  
Raymond Jackson ◽  
Hongxian He ◽  
Quinn Zhu ◽  
Seung-Pyo Hong
Keyword(s):  
Yarrowia Lipolytica ◽  
Lipid Accumulation ◽  
Oleaginous Yeast ◽  
De Novo ◽  
Lipid Synthesis ◽  
Omega 3 ◽  
Wild Type ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Dry Cell Weight

ABSTRACTIn the oleaginous yeastYarrowia lipolytica,de novolipid synthesis and accumulation are induced under conditions of nitrogen limitation (or a high carbon-to-nitrogen ratio). The regulatory pathway responsible for this induction has not been identified. Here we report that the SNF1 pathway plays a key role in the transition from the growth phase to the oleaginous phase inY. lipolytica. Strains with aY. lipolyticasnf1(Ylsnf1) deletion accumulated fatty acids constitutively at levels up to 2.6-fold higher than those of the wild type. When introduced into aY. lipolyticastrain engineered to produce omega-3 eicosapentaenoic acid (EPA),Ylsnf1deletion led to a 52% increase in EPA titers (7.6% of dry cell weight) over the control. Other components of theY. lipolyticaSNF1 pathway were also identified, and their function in limiting fatty acid accumulation is suggested by gene deletion analyses. Deletion of the gene encoding YlSnf4, YlGal83, or YlSak1 significantly increased lipid accumulation in both growth and oleaginous phases compared to the wild type. Furthermore, microarray and quantitative reverse transcription-PCR (qRT-PCR) analyses of theYlsnf1mutant identified significantly differentially expressed genes duringde novolipid synthesis and accumulation inY. lipolytica. Gene ontology analysis found that these genes were highly enriched with genes involved in lipid metabolism. This work presents a new role for Snf1/AMP-activated protein kinase (AMPK) pathways in lipid accumulation in this oleaginous yeast.

scholarly journals Spot 14: A Marker of Aggressive Breast Cancer and a Potential Therapeutic Target

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4048-4055 ◽  
Author(s):  
William B. Kinlaw ◽  
Jennifer L. Quinn ◽  
Wendy A. Wells ◽  
Christopher Roser-Jones ◽  
Joel T. Moncur
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Therapeutic Target ◽  
Milk Fat ◽  
Breast Cancer Cells ◽  
De Novo ◽  
Lipid Synthesis ◽  
Breast Cancers ◽  
Spot 14 ◽  
Aggressive Breast Cancer

Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related hormones to genes required for long-chain fatty acid synthesis. In mammary gland, S14 is important for both epithelial proliferation and milk fat production. The S14 gene is amplified in some breast cancers and is strongly expressed in most. High expression of S14 in primary invasive breast cancer is conspicuously predictive of recurrence. S14 mediates the induction of lipogenesis by progestin in breast cancer cells and accelerates their growth. Conversely, S14 knockdown impairs de novo lipid synthesis and causes apoptosis. We found that breast cancer cells do not express lipoprotein lipase (LPL) and hypothesize that they do not have access to circulating lipids unless the local environment supplies it. This may explain why primary breast cancers with low S14 do not survive transit from the LPL-rich mammary fat pad to areas devoid of LPL, such as lymph nodes, and thus do not appear as distant metastases. Thus, S14 is a marker for aggressive breast cancer and a potential target as well. Future effort will center on validation of S14 as a therapeutic target and producing antagonists of its action.

scholarly journals Toxoplasma gondii myosins B/C

2001 ◽  
Vol 155 (4) ◽  
pp. 613-624 ◽  
Author(s):  
Frédéric Delbac ◽  
Astrid Sänger ◽  
Eva M. Neuhaus ◽  
Rolf Stratmann ◽  
James W. Ajioka ◽  
...  
Keyword(s):  
Cell Division ◽  
Toxoplasma Gondii ◽  
Daughter Cell ◽  
Gliding Motility ◽  
Apicomplexan Parasites ◽  
Daughter Cells ◽  
Membrane Complex ◽  
Alternatively Spliced ◽  
Butanedione Monoxime ◽  
Inner Membrane Complex

In apicomplexan parasites, actin-disrupting drugs and the inhibitor of myosin heavy chain ATPase, 2,3-butanedione monoxime, have been shown to interfere with host cell invasion by inhibiting parasite gliding motility. We report here that the actomyosin system of Toxoplasma gondii also contributes to the process of cell division by ensuring accurate budding of daughter cells. T. gondii myosins B and C are encoded by alternatively spliced mRNAs and differ only in their COOH-terminal tails. MyoB and MyoC showed distinct subcellular localizations and dissimilar solubilities, which were conferred by their tails. MyoC is the first marker selectively concentrated at the anterior and posterior polar rings of the inner membrane complex, structures that play a key role in cell shape integrity during daughter cell biogenesis. When transiently expressed, MyoB, MyoC, as well as the common motor domain lacking the tail did not distribute evenly between daughter cells, suggesting some impairment in proper segregation. Stable overexpression of MyoB caused a significant defect in parasite cell division, leading to the formation of extensive residual bodies, a substantial delay in replication, and loss of acute virulence in mice. Altogether, these observations suggest that MyoB/C products play a role in proper daughter cell budding and separation.

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