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.

The PARP and rRNA promoters of Trypanosoma brucei are composed of dissimilar sequence elements that are functionally interchangeable

1994 ◽  
Vol 14 (9) ◽  
pp. 5804-5811
Author(s):  
L Janz ◽  
C Clayton
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase I ◽  
Surface Proteins ◽  
Surface Glycoprotein ◽  
African Trypanosomes ◽  
Sequence Elements ◽  
Major Surface Proteins ◽  
Major Surface ◽  
Polymerase I ◽  
Repetitive Protein

The African trypanosomes express two major surface proteins, the variant surface glycoprotein (VSG) and the procyclic acidic repetitive protein (PARP). The RNA polymerase that transcribes the VSG and PARP genes shares many characteristics with RNA polymerase I. We show that although there is very little similarity in nucleotide sequence, the functional structure of a trypanosome rRNA promoter is almost identical to that of the PARP promoter. Further, domains from the PARP promoter can functionally substitute for the corresponding parts of the rRNA promoter, and vice versa.

The major cell surface glycoprotein procyclin is a receptor for induction of a novel form of cell death in African trypanosomes in vitro

2000 ◽  
Vol 111 (2) ◽  
pp. 333-349 ◽  
Author(s):  
Terry W Pearson ◽  
Robert P Beecroft ◽  
Susan C Welburn ◽  
Stefan Ruepp ◽  
Isabel Roditi ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Surface ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
African Trypanosomes

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 Site of palmitoylation of a phospholipase C-resistant glycosylphosphatidylinositol membrane anchor

1992 ◽  
Vol 284 (2) ◽  
pp. 297-300 ◽  
Author(s):  
M A J Ferguson
Keyword(s):  
Phospholipase C ◽  
Trypanosoma Brucei ◽  
Periodate Oxidation ◽  
Membrane Anchor ◽  
Glycosyl Phosphatidylinositol ◽  
Oxidation Analysis ◽  
Inositol Ring ◽  
Repetitive Protein

The site of palmitoylation of the phosphatidylinositol moiety of the glycosyl-phosphatidylinositol membrane anchor of Trypanosoma brucei procyclic acidic repetitive protein was studied by using periodate oxidation. Analysis of the products by g.c.-m.s. allowed the assignment of 40 and 60% of the palmitate to the 2-position and the 3-position respectively of the myo-inositol ring.

scholarly journals The N-terminal domain of human urokinase receptor contains two distinct regions critical for ligand recognition

Blood ◽  
1993 ◽  
Vol 82 (9) ◽  
pp. 2719-2729 ◽  
Author(s):  
JJ Pollanen
Keyword(s):  
Surface Glycoprotein ◽  
Alanine Scanning Mutagenesis ◽  
Cell Surface Glycoprotein ◽  
Glycosyl Phosphatidylinositol ◽  
Terminal Domain ◽  
Binding Function ◽  
Activating Receptors ◽  
Type Plasminogen Activator ◽  
High Affinity Receptor ◽  
Species Specific

Abstract The high-affinity receptor that binds human urokinase-type plasminogen activator (hu-PAR) is a glycosyl-phosphatidylinositol (GPI)-anchored cell-surface glycoprotein that belongs to the Ly-6 superfamily of T- cell-activating receptors. Binding of urokinase (u-PA) to u-PAR is species-specific, since neither murine (mu-PAR) nor hu-PAR binds u-PA from the other species. I designed and analyzed a series of exchanges between hu-PAR and mu-PAR in the N-terminal first domain to which ligand-binding function had been independently mapped. Introduction of as few as 13 murine residues (six of 13 variables) into the N-terminal region of hu-PAR abrogated binding to recombinant human pro-u-PA, whereas the opposite chimera, a mu-PAR carrying six of 13 human residues, was positive for binding. Within this region, the mu-PAR domain 1 could be minimally humanized to bind human pro-u-PA by a substitution of as few as four of the six nonconserved residues, thereby identifying the residues arginine-2, lysine-7, threonine-8, and glycine-10 as important in determining binding specificity. By alanine- scanning mutagenesis, a second recognition site within domain 1 was discovered between residues 47 and 53, a segment that is fully conserved between the human and the mouse receptors. Taken together, these results provide identification of two confined subregions within the N-terminal domain of hu-PAR critically involved in pro-u-PA recognition.

scholarly journals Size polymorphisms due to changes in the number of O-glycosylated tandem repeats in the Dictyostelium discoideum glycoprotein PsA.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 749-756
Author(s):  
A A Gooley ◽  
R Marshchalek ◽  
K L Williams
Keyword(s):  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Tandem Repeats ◽  
Allelic Variation ◽  
Surface Glycoprotein ◽  
Crossing Over ◽  
Globular Domain ◽  
Cell Surface Glycoprotein ◽  
Ancestral Gene ◽  
Repeat Domain

Abstract The molecular weight polymorphism in the Dictyostelium discoideum cell surface glycoprotein PsA is due to incremental copies of an O-glycosylated tandem tetrapeptide repeat. Allelic variation at the pspA locus results in a PsA glycoprotein with three, four or five tandem copies of Pro-Thr-Val-Thr. The simplest explanation for the origin of this polymorphism is an unequal crossing over event in the ancestral gene containing four copies. Each Thr in the tandem repeat is substituted with carbohydrate, which is completely absent from PsA in strains carrying a glycosylation defective modB mutation. Glycosylated tandem repeats appear to be a common feature of cell surface glycoproteins which are characterized by short domains rich in Pro and Thr or Ser. It is probable that the glycosylated repeat domain acts as a "spacer" peptide that projects the globular domain above the glycocalyx.

scholarly journals Turnover of Variant Surface Glycoprotein in Trypanosoma brucei Is a Bimodal Process

mBio ◽  
2021 ◽  
Author(s):  
Paige Garrison ◽  
Umaer Khan ◽  
Michael Cipriano ◽  
Peter J. Bush ◽  
Jacquelyn McDonald ◽  
...  
Keyword(s):  
Immune System ◽  
Trypanosoma Brucei ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Host Immune System ◽  
Membrane Anchor ◽  
African Trypanosomes ◽  
Hydrolysis Of

African trypanosomes, the protozoan agent of human African trypanosomaisis, avoid the host immune system by switching expression of the variant surface glycoprotein (VSG). VSG is a long-lived protein that has long been thought to be turned over by hydrolysis of its glycolipid membrane anchor.

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