Trypanosome metabolism of myristate, the fatty acid required for the variant surface glycoprotein membrane anchor

Doering, Tamara L.; Pessin, Melissa S.; Hoff, E.; Hart, Gerald W.; Raben, Daniel M.; Englund, Paul T.

doi:10.1016/s0021-9258(18)98338-9

Cited by 46 publications

(14 citation statements)

References 43 publications

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“…Indeed, at least in some culture conditions, myristate is readily chain elongated in T. brucei to palmitate and stearate. 53 It is conceivable that YnMyr and YnPal are processed by chain elongation/reduction by the trypanosome fatty acid biosynthetic machinery and incorporated into the VSG and other proteins; because processing occurs at the carboxyl end of the lipid, this would be expected to conserve the alkyne tag. Further work will be required to explore this possibility.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Global Profiling and Inhibition of Protein Lipidation in Vector and Host Stages of the Sleeping Sickness Parasite Trypanosoma brucei

et al. 2016

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The enzyme N-myristoyltransferase (NMT) catalyzes the essential fatty acylation of substrate proteins with myristic acid in eukaryotes and is a validated drug target in the parasite Trypanosoma brucei, the causative agent of African trypanosomiasis (sleeping sickness). N-Myristoylation typically mediates membrane localization of proteins and is essential to the function of many. However, only a handful of proteins are experimentally validated as N-myristoylated in T. brucei. Here, we perform metabolic labeling with an alkyne-tagged myristic acid analogue, enabling the capture of lipidated proteins in insect and host life stages of T. brucei. We further compare this with a longer chain palmitate analogue to explore the chain length-specific incorporation of fatty acids into proteins. Finally, we combine the alkynyl-myristate analogue with NMT inhibitors and quantitative chemical proteomics to globally define N-myristoylated proteins in the clinically relevant bloodstream form parasites. This analysis reveals five ARF family small GTPases, calpain-like proteins, phosphatases, and many uncharacterized proteins as substrates of NMT in the parasite, providing a global view of the scope of this important protein modification and further evidence for the crucial and pleiotropic role of NMT in the cell.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Global Profiling and Inhibition of Protein Lipidation in Vector and Host Stages of the Sleeping Sickness Parasite Trypanosoma brucei

et al. 2016

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“…Also, the different FA products produced in BSFs and PCFs can be explained by selective up-or downregulation of ELO3 (Morita et al, 2000). Another example comes from our previous report that BSFs grown in medium containing 5% serum efficiently elongate exogenous [ 3 H]myristate to palmitate and stearate, whereas trypanosomes in whole blood do not (Doering et al, 1993). Whole blood has 20 times more palmitate and stearate than media with 5% serum.…”

Section: Regulation Of the Elo Pathwaymentioning

confidence: 99%

“…The malonyl-CoA is formed by an acetyl-CoA carboxylase, probably in the cytosol, and NADPH can be produced either by oxidation of malate to pyruvate by a cytosolic malic enzyme (van Weelden et al, 2005) or by the pentose phosphate shunt, which may be localized in both the cytosol and the glycosomes (Duffieux et al, 2000). It is important to note that the ELO3 component of the pathway can act as a conventional ELO system, elongating exogenously supplied myristate to palmitate and stearate (Doering et al, 1993). In addition, ELO4 acts as a conventional polyunsaturated FA elongase in that it elongates arachidonoyl-CoA (C20:4) to C22:4.…”

Section: Substrates For Fatty Acid Synthesismentioning

confidence: 99%

“…It was long believed that they were unable to synthesize FAs de novo (Dixon et al, 1971) and that they acquired all FAs, including myristate, from the host blood. Although trypanosomes salvage myristate efficiently (Doering et al, 1993), the myristate concentration in blood is hardly adequate to support GPI myristoylation at high parasite densities (Paul et al, 2001). Several years ago we questioned whether trypanosomes synthesize FAs and discovered that indeed they do (Morita et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Fatty Acid Synthesis by Elongases in Trypanosomes

Lee

Stephens

Paul

et al. 2006

Cell

133

182

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All eukaryotic and prokaryotic organisms are thought to synthesize fatty acids using a type I or type II synthase. In addition, eukaryotes extend pre-existing long chain fatty acids using microsomal elongases (ELOs). We have found that Trypanosoma brucei, a eukaryotic human parasite that causes sleeping sickness, uses three elongases instead of type I or type II synthases for the synthesis of nearly all its fatty acids. Trypanosomes encounter diverse environments during their life cycle with different fatty acid requirements. The tsetse vector form requires synthesis of stearate (C18), whereas the bloodstream form needs myristate (C14). We find that trypanosome fatty acid synthesis is modular, with ELO1 converting C4 to C10, ELO2 extending C10 to C14, and ELO3 elongating C14 to C18. In blood, ELO3 downregulation favors myristate synthesis, whereas low concentrations of exogenous fatty acids in cultured parasites cause upregulation of the entire pathway, allowing the parasite to adapt to different environments.

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“…It is possible that the insect stage has all the other remodelling enzymes but lacks the inositol deacylas e which is needed to generate the appropriate GPI precursor (Gu È ther and Ferguson 1995). The function of fatty acid remodelling in trypanosome s is unknown, although it is likely to be important based on the highly selective nature of these reactions , the specialize d metabolis m of myristic acid in trypanosome s (Doering et al 1993) and the fact that myristic acid analogue s which are incorporate d into anchor precursors and protein-linked GPIs are toxic (Doering et al 1991). Furthermore , the alkylacylglycerol moieties of free GPIs in Leishmania mexicana also undergo fatty acid remodelling with incorporation of myristic acid into the sn-2 position (Ralton and McConville 1998), suggesting a general requirement for this type of lipid composition.…”

Section: Species -Specific Complexity In Gpi Assemblymentioning

confidence: 99%

Recent developments in the cell biology and biochemistry of glycosylphosphatidylinositol lipids (Review)

McConville

Menon²

2000

Molecular Membrane Biology

136

121

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Glycosylphosphatidylinositols (GPIs) represent an abundant and ubiquitous class of eukaryotic glycolipids. Although these structures were originally discovered in the form of GPI-anchored cell surface glycoproteins, it is becoming increasingly clear that a significant proportion of the GPI synthetic output of a cell is not directed to protein anchoring. Indeed, pools of non-protein-linked GPIs can approach 10(7) molecules per cell in some cell types, especially the protozoa, with a large proportion of these molecules being displayed at the cell surface. Recent studies which form the subject of this review indicate that there is (a) considerable diversity in the range of structural modifications found on GPI glycolipids within and between species and cell types, (b) complexity in the topological arrangement of the GPI biosynthetic pathway in the endoplasmic reticulum, and (c) spatial restriction of the biosynthetic pathway within the endoplasmic reticulum. Furthermore, consistent with additional functional roles for these lipids beyond serving as protein anchor precursors, products of the GPI biosynthetic pathway appear to be widely distributed in the cellular endomembrane system. These studies indicate that there is still much to learn about the organization of glycolipid biosynthetic pathways in eukaryotic cells, the nature and subcellular distribution of the lipid products of these pathways, and the function of these lipids within cells.

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Trypanosome metabolism of myristate, the fatty acid required for the variant surface glycoprotein membrane anchor

Cited by 46 publications

References 43 publications

Global Profiling and Inhibition of Protein Lipidation in Vector and Host Stages of the Sleeping Sickness Parasite Trypanosoma brucei

Global Profiling and Inhibition of Protein Lipidation in Vector and Host Stages of the Sleeping Sickness Parasite Trypanosoma brucei

Fatty Acid Synthesis by Elongases in Trypanosomes

Recent developments in the cell biology and biochemistry of glycosylphosphatidylinositol lipids (Review)

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