scholarly journals Developmentally regulated, phospholipase C-mediated release of the major surface glycoprotein of amastigotes of Trypanosoma cruzi.

1988 ◽  
Vol 167 (2) ◽  
pp. 300-314 ◽  
Author(s):  
N W Andrews ◽  
E S Robbins ◽  
V Ley ◽  
K S Hong ◽  
V Nussenzweig
Keyword(s):  
Trypanosoma Cruzi ◽  
Phospholipase C ◽  
Myristic Acid ◽  
Surface Glycoprotein ◽  
Developmentally Regulated ◽  
African Trypanosomes ◽  
Glycosyl Phosphatidylinositol ◽  
Major Surface Glycoprotein ◽  
Major Stage ◽  
Major Surface

The surface of amastigotes of Trypanosoma cruzi is covered by Ssp-4, a major stage-specific glycoprotein. Ssp-4 is anchored to the cell membrane by GPI. It can be metabolically labeled with [3H]myristic acid, and is converted into a hydrophilic form by treatment with the glycan-specific phospholipase C of T. brucei, or after lysis of the parasites in non-ionic detergents. The hydrophilic form of Ssp-4 is recognized by antibodies to the cross-reactive determinant of the variant surface glycoprotein of African trypanosomes. Ssp-4 is progressively shed during the intra- or extracellular development of amastigotes preceding their transformation into epi- and trypomastigotes. We show here that T. cruzi contains a phospholipase C and that most shed Ssp-4 is hydrophilic, does not contain myristic acid, and reacts with anti-CRD. These observations provide strong evidence that phospholipase C mediates the release of this glycosyl-phosphatidylinositol-anchored protein under physiological conditions, as the parasite undergoes differentiation.

scholarly journals Episomal Expression of Specific Sense and Antisense mRNAs in Leishmania amazonensis: Modulation of gp63 Level in Promastigotes and Their Infection of Macrophages In Vitro

2000 ◽  
Vol 68 (1) ◽  
pp. 80-86 ◽  
Author(s):  
De-Qiao Chen ◽  
Bala Krishna Kolli ◽  
Nagendra Yadava ◽  
Hong Gang Lu ◽  
Alice Gilman-Sachs ◽  
...  
Keyword(s):  
Kinetic Studies ◽  
Single Copy ◽  
Antisense Transcription ◽  
Leishmania Amazonensis ◽  
Surface Glycoprotein ◽  
Major Surface Glycoprotein ◽  
Wild Type Clone ◽  
Major Surface ◽  
Specific Sense

ABSTRACT The major surface glycoprotein (gp63) of Leishmania amazonensis is a metalloprotease implicated in the infection of mammalian macrophages. The expression of gp63 and its participation in this infection were further examined by modulating the level of this molecule in a virulent gp63-abundant wild-type clone. Promastigotes were transfected with gp63 genes cloned into aLeishmania-specific vector in two different orientations, leading to the expression of gp63 sense and antisense RNAs. With increasing selective pressure, cell surface gp63 was increasingly augmented in the transfectants with sense transcripts and suppressed to a very low level in those with antisense transcripts. Thus, the expression of gp63 from chromosomal, repetitive genes is not stringently regulated at the protein level and can be substantially reduced by episomal antisense transcription of a single copy. The transfectants differed significantly only in the level of gp63, thereby allowing specific evaluation of this molecule in leishmanial infection of macrophages in vitro. Kinetic studies of infection in vitro indicate that gp63 plays a role not only in the binding of this parasite to these macrophages but also in its intramacrophage survival and replication.

Evidence for glycosyl-phosphatidylinositol anchoring of Toxoplasma gondii major surface antigens

1989 ◽  
Vol 9 (10) ◽  
pp. 4576-4580
Author(s):  
S Tomavo ◽  
R T Schwarz ◽  
J F Dubremetz
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Toxoplasma Gondii ◽  
Phospholipase C ◽  
Surface Antigens ◽  
Water Soluble ◽  
Radioactive Label ◽  
Glycosyl Phosphatidylinositol ◽  
Major Surface

The four major surface antigens of Toxoplasma gondii tachyzoites (P43, P35, P30, and P22) were made water soluble by phosphatidylinositol-specific phospholipase C (PI-PLC). These antigens were biosynthetically labeled with 3H-fatty acids, [3H]ethanolamine, and [3H]carbohydrates. Treatment of 3H-fatty-acid-labeled parasite lysates with PI-PLC removed the radioactive label from these antigens. A cross-reacting determinant was exposed on these antigens after PI-PLC treatment.

scholarly journals A simple purification of procyclic acidic repetitive protein and demonstration of a sialylated glycosyl-phosphatidylinositol membrane anchor

1993 ◽  
Vol 291 (1) ◽  
pp. 51-55 ◽  
Author(s):  
M A Ferguson ◽  
P Murray ◽  
H Rutherford ◽  
M J McConville
Keyword(s):  
Hydrophobic Interaction Chromatography ◽  
Glycosylation Site ◽  
Surface Glycoprotein ◽  
Membrane Anchor ◽  
Cell Surface Glycoprotein ◽  
African Trypanosomes ◽  
Glycosyl Phosphatidylinositol ◽  
Repeat Domain ◽  
Rapid Purification ◽  
Repetitive Protein

The procyclic acidic repetitive protein is the major cell-surface glycoprotein of the insect-dwelling procyclic forms of the Trypanosoma brucei species of African trypanosomes. The glycoprotein contains an acidic Glu-Pro repeat domain, a glycosyl-phosphatidylinositol membrane anchor and a putative asparagine glycosylation site. In this paper we describe a rapid purification scheme for this glycoprotein, using solvent extraction and hydrophobic interaction chromatography, and a partial characterization of the glycosylphosphatidylinositol membrane anchor. The carbohydrate composition of the anchor is extremely unusual; it contains on average nine GlcNAc, nine Gal, and five sialic acid residues. This is the first description of such a heavily substituted and negatively charged anchor. A comparison between the trypanosome procyclic surface and the Leishmania promastigote surface is also presented.

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