Structural analysis of a glycosylphosphatidylinositol glycolipid ofLeishmania donovani

A glycosylphosphatidylinositol (GPI) glycolipid antigen recognized by sera from patients with visceral leishmaniasis was isolated from Leishmania donovani promastigotes. The carbohydrate moiety was cleaved from the lipid part by digestion with specific phosphatidylinositol phospholipase C. After separation, structural analysis was carried out on the phosphorylated inositol oligosaccharide and the alkylacyl glycerol. The following major structures were found: [formula: see text] The presence of the conserved sequence Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN-PI of glycosyl phosphatidylinositol protein anchors in this antigen may be consistent with a precursor role of Leishmania glycosyl phosphatidylinositol anchored proteins for this glycolipid.     

Activation of Toll-like receptor-2 by glycosylphosphatidylinositol anchors from a protozoan parasite.

Glycosylphosphatidylinositol (GPI) anchors and glycoinositolphospholipids (GIPLs) from parasitic protozoa have been shown to exert a wide variety of effects on cells of the host innate immune system. However, the receptor(s) that are triggered by these protozoan glycolipids has not been identified. Here we present evidence that Trypanosoma cruzi-derived GPI anchors and GIPLs trigger CD25 expression on Chinese hamster ovary-K1 cells transfected with CD14 and Toll-like receptor-2 (TLR-2), but not wild-type (TLR-2-deficient) Chinese hamster ovary cells. The protozoan-derived GPI anchors and GIPLs containing alkylacylglycerol and saturated fatty acid chains or ceramide were found to be active in a concentration range of 100 nM to 1 microM. More importantly, the GPI anchors purified from T. cruzi trypomastigotes, which contain a longer glycan core and unsaturated fatty acids in the sn-2 position of the alkylacylglycerolipid component, triggered TLR-2 at subnanomolar concentrations. We performed experiments with macrophages from TLR-2 knockout and TLR-4 knockout mice, and found that TLR-2 expression appears to be essential for induction of IL-12, TNF-alpha, and NO by GPI anchors derived from T. cruzi trypomastigotes. Thus, highly purified GPI anchors from T. cruzi parasites are potent activators of TLR-2 from both mouse and human origin. The activation of TLR-2 may initiate host innate defense mechanisms and inflammatory response during protozoan infection, and may provide new strategies for immune intervention during protozoan infections.     

The surface glycoconjugates of trypanosomatid parasites.

Insect-transmitted protozoan parasites of the order Kinetoplastida, suborder Trypanosomatina, include Trypanosoma brucei (aetiological agent of African sleeping sickness), Trypanosoma cruzi (aetiological agent of Chagas'' disease in South and Central America) and Leishmania spp. (aetiological agents of a variety of diseases throughout the tropics and sub-tropics). The structures of the most abundant cell-surface molecules of these organisms is reviewed and correlated with the different modes of parasitism of the three groups of parasites. The major surface molecules are all glycosylphosphatidylinositol (GPI)-anchored glycoproteins, such as the variant surface glycoproteins of T. brucei and the surface mucins of T. cruzi, or complex glycophospholipids, such as the lipophosphoglycans and glycoinositolphospholipids of the leishmanias. Significantly, all of the aforementioned structures share a motif of Man alpha 1-4GlcN alpha 1-6-myo-inositol-1-HPO4-lipid and can therefore be considered to be members of a GPI superfamily.     

Structural studies on the glycosylphosphatidylinositol membrane anchor of Trypanosoma cruzi 1G7-antigen. The structure of the glycan core.

The 1G7-antigen is expressed by the infective metacyclic trypomastigote stage of the protozoan parasite Trypanosoma cruzi. The 1G7-antigen is a 90-kDa glycoprotein, present at about 40,000 copies/cell, which is anchored in the plasma membrane via a glycosylphosphatidylinositol (GPI) membrane anchor. The glycan of the GPI anchor has been isolated from immunopurified 1G7-antigen and its structure determined using a combination of methylation linkage analysis and exoglycosidase sequencing. The structure of the glycan is Man alpha 1-2Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcNH2. The glucosamine residue is in glycosidic linkage to a phosphatidylinositol moiety. The penultimate nonreducing alpha-Man residue is substituted with phosphate, which is most likely part of an ethanolamine phosphate bridge linking the GPI anchor to the 1G7-antigen polypeptide. The glycan sequence was obtained from 1.1 nmol of glycoprotein isolated from a detergent lysate of whole cells. The procedures reported here represent a high sensitivity protocol for determining GPI glycan structures from small quantities of biological material. The structure of the 1G7-antigen GPI anchor is consistent with the conserved core structure of all GPI anchors analyzed to date and is similar to that of the T. cruzi lipopeptidophosphoglycan. The biosynthesis of GPI anchors and lipopeptidophosphoglycan in T. cruzi is discussed in the light of this structural homology.     

Structures of glycosphingolipids isolated from human granulocytes. The presence of a series of linear poly-N-acetyllactosaminylceramide and its significance in glycolipids of whole blood cells

Structures of glycolipids isolated from human granulocytes were elucidated by fast atom bombardment-mass spectrometry, methylation analysis, and exo- and endoglycosidase treatment. All neutral glycolipids, with saccharide residues ranging from 2 to 10, were found to have linear N-acetyllactosaminyl backbones. The majority of neutral glycolipids contain one or two fucosyl residues attached to N-acetylglucosamine residues through the Fuc alpha 1----3 linkage and were reactive with the monoclonal antibody specific to Gal beta 1----4(Fuc alpha 1----3)GlcNAc, the Lex structure. Their general structure can be expressed as follows: (formula; see text) where n = 0-3. Glycolipids containing sialic acid (gangliosides) were also found to have linear N-acetyllactosaminyl backbones with sialic acid joined to this backbone by either alpha 2----3 or alpha 2----6 linkage. The gangliosides have the following general structure: (formula; see text) where n = 0-3. The ceramide was composed of sphingosine with d18:1 as the long-chain base and C16:0 (as a major component) or C24:1 (as a minor component) fatty acid. Analysis of glycolipids isolated from granulocytes, erythrocytes, and whole blood cells revealed that, among the glycolipids prepared from the whole blood cells, dihexaosylceramide, lactoneotetraosylceramide, and the above described linear lactoneo series neutral glycolipids are present in granulocytes but barely present in erythrocytes.     

Phylogeny of Trypanosomatidae and Bodonidae (Kinetoplastida) based on 18S rRNA: evidence for paraphyly of Trypanosoma and six other genera

Phylogenetic analysis of 18S rRNA sequences from the families Trypanosomatidae and Bodonidae (Eugelenozoa: Kinetoplastida) was conducted using a variety of methods. Unlike previous analyses using unrooted trees and/or smaller numbers of sequences, the analysis did not support monophyly of the genus Trypanosoma, which includes the major human parasites T. cruzi (cause of Chagas' disease) and T. brucei (cause of African sleeping sickness). The section Salivaria of the genus Trypanosoma fell outside a cluster that includes the section Stercoraria of the genus Trypanosoma, along with members of the genera Leishmania, Endotrypanum, Leptomonas, Herpetomonas, Phytomonas, Crithidia, and Blastocrithidia. The phylogenetic analysis also indicated that the genera Bodo, Cryptobia, Leptomonas, Herpetomonas, Crithidia, and Blastocrithidia are polyphyletic. The results suggested that parasitism of vertebrates has probably arisen independently a number of times within the Trypanosomatidae.     

Structure of the glycosyl-phosphatidylinositol membrane anchor of the Leishmania major promastigote surface protease

In common with many other plasma membrane glycoproteins of eukaryotic origin, the promastigote surface protease (PSP) of the protozoan parasite Leishmania contains a glycosyl-phosphatidylinositol (GPI) membrane anchor. The GPI anchor of Leishmania major PSP was purified following proteolysis of the PSP and analyzed by two-dimensional 1H-1H NMR, compositional and methylation linkage analyses, chemical and enzymatic modifications, and amino acid sequencing. From these results, the structure of the GPI-containing peptide was found to be Asp-Gly-Gly-Asn-ethanolamine-PO4-6Man alpha 1-6Man alpha 1-4GlcN alpha 1-6myo-inositol-1-PO4-(1-alkyl-2-acyl-glycerol). The glycan structure is identical to the conserved glycan core regions of the GPI anchor of Trypanosoma brucei variant surface glycoprotein and rat brain Thy-1 antigen, supporting the notion that this portion of GPIs are highly conserved. The phosphatidylinositol moiety of the PSP anchor is unusual, containing a fully saturated, unbranched 1-O-alkyl chain (mainly C24:0) and a mixture of fully saturated unbranched 2-O-acyl chains (C12:0, C14:0, C16:0, and C18:0). This lipid composition differs significantly from those of the GPIs of T. brucei variant surface glycoprotein and mammalian erythrocyte acetylcholinesterase but is similar to that of a family of glycosylated phosphoinositides found uniquely in Leishmania.     

Trypanosoma cruzi oleate desaturase: molecular characterization and comparative analysis in other trypanosomatids

Trypanosoma cruzi lipids contain a high content of unsaturated fatty acids, primarily oleic acid (C18:1) and linoleic acid (C18:2). Previous data suggest that this parasite is able to convert oleic acid into linoleic acid; humans are not able to do this. Presently, we show that T. cruzi has a gene with high similarity to the delta12 (omega6)-oleate desaturase from plants. Northern blot analysis of the oleate desaturase gene from T. cruzi (OD(Tc)) indicated that this gene is transcribed in epimastigote, amastigote, and trypomastigote forms. Pulsed-field analysis showed that OD(Tc) is located at distinct chromosomal bands on distinct T. cruzi phylogenetic groups. In addition, the chromoblot analysis demonstrated the presence of homologous OD(Tc) genes in several trypanosomatids; namely, Crithidia fasciculata, Herpetomonas megaseliae, Leptomonas seymouri, Trypanosoma freitasi, Trypanosoma rangeli, Trypanosoma lewisi, Blastocrithidia sp., Leishmania amazonensis, Endotrypanum schaudinni, and Trypanosoma conorhini. The native OD(Tc) activity was detected by metabolic labeling and analysis of total fatty acids from epimastigotes and trypomastigotes of T. cruzi, coanomastigotes of C. fasciculata, and promastigotes of L. amazonensis, H. megaseliae, and L. seymouri. The fact that the enzyme oleate desaturase is not present in humans makes it an ideal molecular target for the development of new chemotherapeutic approaches against Chagas disease.     

Properties of phosphoenolpyruvate mutase,the first enzyme in the aminoethylphosphonate biosynthetic pathway in Trypanosoma cruzi

Phosphoenolpyruvate (PEP) mutase catalyzes the conversion of phosphoenolpyruvate to phosphonopyruvate, the initial step in the formation of many naturally occurring phosphonate compounds. The phosphonate compound 2-aminoethylphosphonate is present as a component of complex carbohydrates on the surface membrane of many trypanosomatids including glycosylinositolphospholipids of Trypanosoma cruzi. Using partial sequence information from the T. cruzi genome project we have isolated a full-length gene with significant homology to PEP mutase from the free-living protozoan Tetrahymena pyriformis and the edible mussel Mytilus edulis. Recombinant expression in Escherichia coli confirms that it encodes a functional PEP mutase with a Km apparent of 8 microM for phosphonopyruvate and a kcat of 12 s-1. The native enzyme is a homotetramer with an absolute requirement for divalent metal ions and displays negative cooperativity for Mg2+ (S0.5 0.4 microM; n = 0.46). Immunofluorescence and sub-cellular fractionation indicates that PEP mutase has a dual localization in the cell. Further evidence to support this was obtained by Western analysis of a partial sub-cellular fractionation of T. cruzi cells. Southern and Western analysis suggests that PEP mutase is unique to T. cruzi and is not present in the other medically important parasites, Trypanosoma brucei and Leishmania spp.     

Lea-active heptaglycosylceramide, a hybrid of type 1 and type 2 chain, and the pattern of glycolipids with Lea, Leb, X (Lex), and Y (Ley) determinants in human blood cell membranes (ghosts). Evidence that type 2 chain can elongate repetitively but type 1 chain cannot

Two major glycolipids reactive with the monoclonal anti-Lea antibody have been isolated from human blood cell membranes. One component was identified as lactofucopentaosyl(II)ceramide and the other as a ceramide heptassaccharide with the structure described below: (formula; see text) The structure includes the Lea determinant (type 1 chain) linked to lactoneotetraosylceramide (type 2 chain); thus, it is regarded to be a hybrid between type 1 and 2 chain. In addition, a minor component having the thin-layer chromatographic mobility of a ceramide nonasaccharide, which was reactive to anti-Lea antibody, was detected. No other component with a thin-layer chromatographic mobility slower than the above components and reactive to the anti-Lea antibody was detected. In contrast, a series of slowly migrating glycolipids having X (Lex) determinant (Gal beta 1----4(Fuc alpha 1----3)GlcNAc) was detected. A similar series of long chain glycolipids having Y (Ley) determinant (Fuc alpha 1----2Gal beta 1----4(Fuc1----3)GlcNAc) was detected in human blood cells; in contrast, only one major Leb glycolipid was found with the mobility of a ceramide hexasaccharide. No glycolipid with a long carbohydrate chain composed exclusively of type 1 chain was detected. Thus, chain elongation may proceed through type 2 chain, but not through type 1 chain. Lea and X (Lex) haptens are distributed equally among blood group A, B, and O red blood cells, whereas the quantity of Leb and Y (Ley) haptens is much lower in A and B blood cells than in O blood cells.     

Structure of a triphosphonopentaosylceramide containing 4-O-methyl-N-acetylglucosamine from the skin of the sea hare, Aplysia kurodai

A novel phosphonoglycosphingolipid named SGL-I containing 3 mol of 2-aminoethylphosphonate residues was isolated from the skin of a sea gastropod, Aplysia kurodai. The saccharide moiety of the glycolipid was characterized as 4-O-methyl-GlcNAc alpha 1----4GalNAc alpha-1----3 [6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2] (2-aminoethylphosphonyl----6)Gal beta 1----4(2-aminoethylphosphonyl----6) Glc beta 1----1-ceramide. The major aliphatic components of the ceramide portion were palmitic acid, stearic acid, octadeca-4-sphingenine, and anteisononadeca-4-sphingenine. This glycolipid is unique in containing 4-O-methyl-N-acetylglucosamine and 3 mol of 2-aminoethylphosphonate residues, one of which is attached to C-6 of glucose.     

The activity of diguanidino and 'reversed' diamidino 2,5-diarylfurans versus Trypanosoma cruzi and Leishmania donovani

The in vitro activity of 20 dicationic molecules containing either diguanidino or reversed amidine cationic groups were evaluated versus Trypanosoma cruzi and Leishmania donovani. The most active compounds were in the reversed amidine series and six exhibited IC(50) values of less than 1 micro mol versus T. cruzi and five gave similar values versus L. donovani.     

Glycosylphosphatidylinositol-anchored mucin-like glycoproteins from Trypanosoma cruzi bind to CD1d but do not elicit dominant innate or adaptive immune responses via the CD1d/NKT cell pathway

It has been proposed that self and protozoan-derived GPI anchors are natural ligands of CD1d. In this study, we investigated the ability of GPI anchors from Trypanosoma cruzi to bind to CD1d and mediate activation of NKT cells. We observed that GPI-anchored mucin-like glycoproteins (GPI mucins), glycoinositolphospholipids (GIPLs), and their phosphatidylinositol moieties bind to rCD1d and inhibit the stimulation of a NKT hybridoma by the alpha-galactosylceramide-CD1 complex. However, these GPI anchors and related structures were unable to activate NKT cells in vitro or in vivo. We found that high titers of Ab anti-GPI mucins, but not anti-GIPLs, were detected in sera from wild-type as well as in TAP1(-/-), CD1d(-/-), and MHC class II(-/-) mice after immunization. However, T-dependent anti-GPI mucin Ab isotypes, such as IgG1, IgG2a, IgG2b, and IgG3, were absent on MHC class II(-/-), but were conserved in CD1d(-/-) and TAP1(-/-) mice. Furthermore, we found that CD1d(-/-) mice presented a robust cytokine as well as anti-GPI mucins and anti-GIPL Ab responses, upon infection with T. cruzi parasites. These results indicate that, despite binding to CD1d, GPI mucins and related structures expressed by T. cruzi appear not to evoke dominant CD1d-restricted immune responses in vivo. In contrast, MHC class II is critical for the production of the major Ig G isotypes against GPI mucins from T. cruzi parasites.     

Galactose-containing glycosylphosphatidylinositols in Trypanosoma brucei.

Many eukaryotic surface glycoproteins, including the variant surface glycoproteins (VSGs) of Trypanosoma brucei, are synthesized with a carboxyl-terminal hydrophobic peptide extension that is cleaved and replaced by a complex glycosylphosphatidylinositol (GPI) membrane anchor within 1-5 min of the completion of polypeptide synthesis. We have reported the purification and partial characterization of candidate precursor glycolipids (P2 and P3) from T. brucei. P2 and P3 contain ethanolamine-phosphate-Man alpha 1-2Man alpha 1-6Man alpha 1-GlcN linked glycosidically to an inositol residue, as do all the GPI anchors that have been structurally characterized. The anchors on mature VSGs contain a heterogenously branched galactose structure attached alpha 1-3 to the mannose residue adjacent to the glucosamine. We report the identification of free GPIs that appear to be similarly galactosylated. These glycolipids contain diacylglycerol and alpha-galactosidase-sensitive glycan structures which are indistinguishable from the glycans derived from galactosylated VSG GPI anchors. We discuss the relevance of these galactosylated GPIs to the biosynthesis of VSG GPI anchors.     

Parasite and mammalian GPI biosynthetic pathways can be distinguished using synthetic substrate analogues.

Glycosylphosphatidylinositol (GPI) structures are attached to many cell surface glycoproteins in lower and higher eukaryotes. GPI structures are particularly abundant in trypanosomatid parasites where they can be found attached to complex phosphosaccharides, as well as to glycoproteins, and as mature surface glycolipids. The high density of GPI structures at all life-cycle stages of African trypanosomes and Leishmania suggests that the GPI biosynthetic pathway might be a reasonable target for the development of anti-parasite drugs. In this paper we show that synthetic analogues of early GPI intermediates having the 2-hydroxyl group of the D-myo-inositol residue methylated are recognized and mannosylated by the GPI biosynthetic pathways of Trypanosoma brucei and Leishmania major but not by that of human (HeLa) cells. These findings suggest that the discovery and development of specific inhibitors of parasite GPI biosynthesis are attainable goals. Moreover, they demonstrate that inositol acylation is required for mannosylation in the HeLa cell GPI biosynthetic pathway, whereas it is required for ethanolamine phosphate addition in the T.brucei GPI biosynthetic pathway.     

Characterization of two novel pyruvylated glycosphingolipids containing 2'-aminoethylphosphoryl(-->6)-galactose from the nervous system of Aplysia kurodai.

Two novel acidic glycosphingolipids containing pyruvylated galactose were purified from the nervous tissue of Aplysia kurodai by successive Iatrobeads column chromatographies. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structures of these acidic glycosphingolipids, named F-9 and FGL-I, were determined to be: [3,4-O-(S-1-carboxyethylidene)]Gal beta 1-->3 GalNAc alpha 1-->3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1-->2] (2-aminoethylphosphoryl 1-->6)Gal beta 1-->4Glc beta 1-->1ceramide and [3,4-O-(S-1-carboxyethylidene)] Gal beta 1-->3GalNAc alpha 1-->3(Fuc alpha 1-->2)(2-aminoethylphosphonyl-->6 Gal beta 1-->4Glc beta 1-->1ceramide, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, pyruvylated glycosphingolipids containing phosphoethanolamine in addition to or in place of 2-aminoethylphosphonate are present in the nervous system of Aplysia.     

GUP1 of Saccharomyces cerevisiae encodes an O-acyltransferase involved in remodeling of the GPI anchor

The anchors of mature glycosylphosphatidylinositol (GPI)-anchored proteins of Saccharomyces cerevisiae contain either ceramide or diacylglycerol with a C26:0 fatty acid in the sn2 position. The primary GPI lipid added to newly synthesized proteins in the ER consists of diacylglycerol with conventional C16 and C18 fatty acids. Here we show that GUP1 is essential for the synthesis of the C26:0-containing diacylglycerol anchors. Gup1p is an ER membrane protein with multiple membrane-spanning domains harboring a motif that is characteristic of membrane-bound O-acyl-transferases (MBOAT). Gup1Delta cells make normal amounts of GPI proteins but most mature GPI anchors contain lyso-phosphatidylinositol, and others possess phosphatidylinositol with conventional C16 and C18 fatty acids. The incorporation of the normal ceramides into the anchors is also disturbed. As a consequence, the ER-to-Golgi transport of the GPI protein Gas1p is slow, and mature Gas1p is lost from the plasma membrane into the medium. Gup1Delta cells have fragile cell walls and a defect in bipolar bud site selection. GUP1 function depends on the active site histidine of the MBOAT motif. GUP1 is highly conserved among fungi and protozoa and the gup1Delta phenotype is partially corrected by GUP1 homologues of Aspergillus fumigatus and Trypanosoma cruzi.     

Effect of glycolipids of Leishmania parasites on human monocyte activity. Inhibition by lipophosphoglycan

Lipophosphoglycan (LPG) and glycosyl phosphatidylinositol Ag (GPI), are glycolipids present on the membrane of Leishmania parasites. Both glycolipids have been chemically characterized. LPG is a polysaccharide of repeating phosphorylated units linked to a phosphocarbohydrate core that is anchored to the membrane by lysoalkyl phosphatidylinositol (PI). The GPI are smaller glycolipids with a structure resembling the phosphocarbohydrate core of the LPG. They are anchored to the membrane by alkyl acyl PI. Their relative abundance, uniqueness of structure, and cellular location suggest a role in interactions of the parasites with host cells. In the present study we examined the effect of LPG and GPI on the activation of human peripheral blood monocytes. Three parameters were studied: the production of IL-1, chemotactic locomotion, and oxidative burst. We found that whereas neither GPI nor LPG directly affected monocyte activity, preincubation of the monocytes with LPG strongly inhibited further activation: The production of IL-1, after stimulation with LPS, was decreased in a dose-dependent manner. Previous incubation with LPG also inhibited chemotactic locomotion of monocytes and neutrophils in response to diacylglycerol, zymosan-activated serum, FMLP and LTB4. Luminol-dependent chemiluminiscence caused by stimulation of the monocytes with streptococci and histone was also inhibited. After fragmentation of the LPG into phosphoglycan and 1-O-alkylglycerol by phosphatidylinositol-phospholipase C, only the phosphoglycan retained inhibitory activity. No difference in inhibitory activity was found between LPG prepared from Leishmania major or Leishmania donovani promastigotes. These results show that the phosphoglycan of LPG inhibits the immunologic response of normal human monocytes and neutrophils, and suggest that LPG may influence the nature of the inflammatory response surrounding infected cells.     

Structural analysis of glycosyl-phosphatidylinositol antigens of Leishmania major

Three glycosyl-phosphatidylinositol glycolipids recognized by antibodies from patients with cutaneous leishmaniasis were extracted from Leishmania major promastigotes by hexane:isopropanol and then purified by thin layer chromatography and LH-20 gel chromatography. Structural analysis was carried out using chemical analyses, fast atom bombardment mass spectrometry, and 1H NMR. The major structures deduced can be summarized as follows: (formula: see text) where n = 0, 1, 2; R1 = (CH2)23-CH3; R2 = (CH2)14-CH3 or (CH2)16-CH3. Alkyl-acyl substitutions in the glycerol backbone showed considerable heterogeneity. These three glycolipids belong to a relatively new class of compounds and may represent sequential steps in the biosynthesis of glycosyl-phosphatidylinositols which anchor proteins or other glycoconjugates to Leishmania cell membranes.     

Inositolphosphoceramide metabolism in Trypanosoma cruzi as compared with other trypanosomatids

Chagas disease is caused by Trypanosoma cruzi and is endemic to North, Central and South American countries. Current therapy against this disease is only partially effective and produces adverse side effects. Studies on the metabolic pathways of T. cruzi, in particular those with no equivalent in mammalian cells, might identify targets for the development of new drugs. Ceramide is metabolized to inositolphosphoceramide (IPC) in T. cruzi and other kinetoplastid protists whereas in mammals it is mainly incorporated into sphingomyelin. In T. cruzi, in contrast to Trypanosoma brucei and Leishmania spp., IPC functions as lipid anchor constituent of glycoproteins and free glycosylinositolphospholipids (GIPLs). Inhibition of IPC and GIPLs biosynthesis impairs differentiation of trypomastigotes into the intracellular amastigote forms. The gene encoding IPC synthase in T. cruzi has been identified and the enzyme has been expressed in a cell-free system. The enzyme involved in IPC degradation and the remodelases responsible for the incorporation of ceramide into free GIPLs or into the glycosylphosphatidylinositols anchoring glycoproteins, and in fatty acid modifications of these molecules of T. cruzi have been understudied. Inositolphosphoceramide metabolism and remodeling could be exploited as targets for Chagas disease chemotherapy.