scholarly journals Surface proteins of Plasmodium falciparum merozoites binding to the erythrocyte receptor, glycophorin.

1984 ◽  
Vol 160 (3) ◽  
pp. 788-798 ◽  
Author(s):  
M E Perkins
Keyword(s):  
Specific Binding ◽  
Surface Proteins ◽  
Malarial Parasite ◽  
Ligand Molecule ◽  
Glycophorin A ◽  
Surface Coat ◽  
Receptor Proteins ◽  
Erythrocyte Surface ◽  
Minor Protein ◽  
A Minor

Invasion of erythrocytes by the malarial parasite is a receptor-mediated process. P. falciparum merozoites recognize and bind to erythrocyte surface sialoglycoproteins, glycophorins A and B, and the glycophorins bind to saturable sites on the merozoite surface. The purpose of the present work was to identify a receptor or ligand molecule on the merozoite surface that mediates binding to the erythrocyte. A fraction containing the sialoglycoproteins was coupled to an acrylamide matrix and incubated with metabolically labeled merozoites. A merozoite protein of 155 kD that labeled prominently with [3H]glycine bound to glycophorin. A minor protein of 130 kD also bound. Both proteins are rich in proline and glycine, poor in methionine, and may be related. The proteins are also stable to heating to 100 degrees C for 10 min. Immunoelectron microscopy demonstrated that the 155 kD and 130 kD proteins are located on the merozoite surface coat. The antibodies significantly inhibited merozoite invasion into erythrocytes and also binding of the proteins to the glycophorin-matrix. The specific binding of the 155-kD and 130-kD proteins to the erythrocyte receptor and the demonstration that they are located on the merozoite surface suggest they could be receptor proteins that mediate binding of the merozoite to the erythrocyte surface.

scholarly journals Inhibitory effects of erythrocyte membrane proteins on the in vitro invasion of the human malarial parasite (Plasmodium falciparum) into its host cell.

1981 ◽  
Vol 90 (3) ◽  
pp. 563-567 ◽  
Author(s):  
M Perkins
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Proteins ◽  
Host Cell ◽  
Malarial Parasite ◽  
Glycophorin A ◽  
Low Concentrations ◽  
Parasite Plasmodium ◽  
Erythrocyte Surface ◽  
Parasite Plasmodium Falciparum

The intracellular development of the erythrocytic stage of the malarial parasite (merozoite) is initiated by the attachment of the parasite to the erythrocyte surface. This paper describes an assay system to investigate Plasmodium falciparum merozoite entry into the host cell and reports on three observations regarding this interaction. (a) Merozoites do not invade human erythrocytes treated with either trypsin or neuraminidase, and both enzymes partially cleave glycophorin A, the major erythrocyte surface sialoglycoprotein. (b) A membrane protein fraction containing glycophorin A will, at low concentrations, inhibit the invasion of isolated merozoites into erythrocytes; no other fractions of membrane proteins have appreciable effects on the reinvasion. (c) Merozoites do not reinvade erythrocytes preincubated with F ab' fragments of antibody prepared against glycophorin A. Together, these three observations imply a role for glycophorin A in the attachment of the malarial parasite to the erythrocyte surface.

scholarly journals Tissue-specific distribution of cross-linked somatostatin receptor proteins in the rat

1992 ◽  
Vol 282 (2) ◽  
pp. 339-344 ◽  
Author(s):  
C B Srikant ◽  
K K Murthy ◽  
Y C Patel
Keyword(s):  
Exocrine Pancreas ◽  
Receptor Protein ◽  
Cross Linking ◽  
Molecular Heterogeneity ◽  
Dependent Manner ◽  
Tissue Specific ◽  
Receptor Proteins ◽  
Specific Distribution ◽  
A Minor ◽  
The Brain

Pharmacological studies have suggested that the somatostatin (SS) receptor is heterogeneous and exhibits SS-14-and SS-28-selective subtypes. Whether such subtypes arise from molecular heterogeneity of the receptor protein has not been definitively established. Previous reports characterizing the molecular properties of the SS receptor by the cross-linking approach have yielded divergent size estimates ranging from 27 kDa to 200 kDa. In order to resolve this discrepancy, as well as to determine whether SS-14 and SS-28 interact with specific receptor proteins, we have cross-linked radioiodinated derivatives of [125I-Tyr11]SS-14 (T*-SS-14) and [Leu8,D-Trp22,125I-Tyr25]SS-28 (LTT*-SS-28) to membrane SS receptors in rat brain, pituitary, exocrine pancreas and adrenal cortex using a number of chemical and photoaffinity cross-linking agents. The labelled cross-linked receptor proteins were analysed by SDS/PAGE under reducing conditions followed by autoradiography. Our findings indicate that the pattern of specifically labelled cross-linked SS receptor proteins is sensitive to the concentration of chemical cross-linking agents such as disuccinimidyl suberate and dithiobis-(succinimidyl propionate). Labelled high-molecular-mass complexes of cross-linked receptor-ligand proteins were observed only when high concentrations of these cross-linkers were employed. Using optimized low concentrations of cross-linkers, however, two major labelled bands of 58 +/- 3 kDa and 27 +/- 2 kDa were detected. These two bands were identified as specifically labelled SS receptor proteins subsequent to cross-linking with a number of photoaffinity cross-linking agents as well. We demonstrate here that the 58 kDa protein is the major SS receptor protein in the rat pituitary, adrenal and exocrine pancreas, whereas the 27 kDa moiety represents the principal form in the brain. Additionally, the presence of a minor specifically labelled band of 32 kDa was detected uniquely in the brain, and a minor labelled protein of 42 kDa was observed in the pancreas. The labelling pattern obtained with LTT*-SS-28 was identical to that observed with T*-SS-14. Labelling of the 27 kDa band by either ligand was inhibited by SS-14 and SS-28 in a dose-dependent manner. Densitometric quantification showed that SS-14 exhibited greater than 2-fold greater potency than SS-28 for inhibiting the labelling of the 27 kDa species. These findings emphasize the need for careful interpretation of cross-linking data obtained for SS receptors, and provide evidence for molecular heterogeneity and for a tissue-specific distribution of the two principal SS receptor proteins.

Functional specificity of jejunal brush-border pteroylpolyglutamate hydrolase in pig

1991 ◽  
Vol 260 (6) ◽  
pp. G865-G872 ◽  
Author(s):  
C. J. Chandler ◽  
D. A. Harrison ◽  
C. A. Buffington ◽  
N. A. Santiago ◽  
C. H. Halsted
Keyword(s):  
Brush Border ◽  
Protein Band ◽  
Major Protein ◽  
Functional Specificity ◽  
Major Protein Band ◽  
Regional Location ◽  
Minor Protein ◽  
A Minor ◽  
Hydrolysis Of

To determine the functional specificity of intestinal brush-border pteroylpolyglutamate hydrolase (PPH), we compared the regional location of in vivo hydrolysis of pteroyltriglutamate (PteGlu3) with the location of activity and immunoreactivity of the enzyme in the pig. After in vivo incubations, PteGlu3 hydrolytic products were recovered from intestinal segments in the jejunum but not from the ileum. Brush-border PPH activity in fractionated mucosa was 10-fold greater in the jejunum than in the ileum, whereas the activity of intracellular PPH was increased in the distal ileum. Antibodies to purified brush-border PPH identified a major protein band at 120 kDa and a minor protein band at 195 kDa in solubilized jejunal brush border. Immunohistochemistry identified the enzyme only on the brush-border surface of the jejunum, whereas an immunoblot of solubilized brush-border membranes identified brush-border PPH in the jejunum but not in the ileum. The parallel of the regional location of in vivo hydrolysis of PteGlu3 with the location of brush-border PPH activity and immunoreactivity demonstrates the functional specificity of this enzyme in folate digestion.

scholarly journals Deletion ofPlasmodium falciparumProtein RON3 Affects the Functional Translocation of Exported Proteins and Glucose Uptake

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Leanne M. Low ◽  
Yvonne Azasi ◽  
Emma S. Sherling ◽  
Matthias Garten ◽  
Joshua Zimmerberg ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Glucose Uptake ◽  
Protein Transport ◽  
Dense Granule ◽  
Vacuolar Membrane ◽  
Malarial Parasite ◽  
Membrane Protein Complex ◽  
Erythrocyte Surface ◽  
Dependent Transport ◽  
Rhoptry Protein

ABSTRACTThe survival ofPlasmodiumspp. within the host red blood cell (RBC) depends on the function of a membrane protein complex, termed thePlasmodiumtranslocon of exported proteins (PTEX), that exports certain parasite proteins, collectively referred to as the exportome, across the parasitophorous vacuolar membrane (PVM) that encases the parasite in the host RBC cytoplasm. The core of PTEX consists of three proteins: EXP2, PTEX150, and the HSP101 ATPase; of these three proteins, only EXP2 is a membrane protein. Studying the PTEX-dependent transport of members of the exportome, we discovered that exported proteins, such as ring-infected erythrocyte surface antigen (RESA), failed to be transported in parasites in which the parasite rhoptry protein RON3 was conditionally disrupted. RON3-deficient parasites also failed to develop beyond the ring stage, and glucose uptake was significantly decreased. These findings provide evidence that RON3 influences two translocation functions, namely, transport of the parasite exportome through PTEX and the transport of glucose from the RBC cytoplasm to the parasitophorous vacuolar (PV) space where it can enter the parasite via the hexose transporter (HT) in the parasite plasma membrane.IMPORTANCEThe malarial parasite within the erythrocyte is surrounded by two membranes.Plasmodiumtranslocon of exported proteins (PTEX) in the parasite vacuolar membrane critically transports proteins from the parasite to the erythrocytic cytosol and membrane to create protein infrastructure important for virulence. The components of PTEX are stored within the dense granule, which is secreted from the parasite during invasion. We now describe a protein, RON3, from another invasion organelle, the rhoptry, that is also secreted during invasion. We find that RON3 is required for the protein transport function of the PTEX and for glucose transport from the RBC cytoplasm to the parasite, a function thought to be mediated by PTEX component EXP2.

scholarly journals Inhibition of malarial parasite invasion by monoclonal antibodies against glycophorin A correlates with reduction in red cell membrane deformability

Blood ◽  
1989 ◽  
Vol 74 (5) ◽  
pp. 1836-1843 ◽  
Author(s):  
G Pasvol ◽  
JA Chasis ◽  
N Mohandas ◽  
DJ Anstee ◽  
MJ Tanner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Membrane ◽  
Red Cells ◽  
Malarial Parasite ◽  
Glycophorin A ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Parasite Invasion ◽  
Surface Molecules ◽  
Fab Fragments

Abstract The effect of well-characterized monoclonal antibodies to red cell surface molecules on the invasion of human red cells by the malarial parasites Plasmodium falciparum and Plasmodium knowlesi was examined. Antibodies to glycophorin A (GP alpha) inhibit invasion for both parasite species, and this is highly correlated with the degree to which they decrease red cell membrane deformability as measured by ektacytometry. This effect on rigidity and invasion was also seen with monovalent Fab fragments. The closer the antibody binding site was to the membrane bilayer, the greater was its effect on inducing membrane rigidity and decreasing parasite invasion. Antibodies to the Wright determinant in particular were the most inhibitory. This differential effect of the various antibodies was not correlated with their binding affinities or the number of sites bound per cell. Antibodies to surface molecules other than GP alpha were without effect. A novel mechanism is described whereby monoclonal antibodies and their Fab fragments directed at determinants on the external surface of red cells might act to inhibit invasion by malarial parasites by altering membrane material properties.

Surface coat proteins of the potato cyst nematode, Globodera rostochiensis

Nematology ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 113-123
Author(s):  
James A. Price ◽  
Terry K. Smith ◽  
John T. Jones
Keyword(s):  
Surface Composition ◽  
Surface Proteins ◽  
Surface Coat ◽  
Coat Proteins ◽  
Cyst Nematodes ◽  
Selective Labelling ◽  
Wide Range ◽  
Genes Encoding ◽  
Surface Coat Proteins ◽  
The Uk

Summary Potato cyst nematodes (PCN) are estimated to cause over £50 million worth of crop losses in the UK each year. It has been shown that the infective juveniles are able to alter their surface composition to avoid damage from host defence mechanisms. However, relatively few proteins present on the cuticle surface of PCN juveniles have been identified. We have developed a method based upon biotinylation that allows selective labelling of proteins present on the cuticle surface of PCN. Isolated proteins can consequently be affinity purified and identified using mass spectrometry proteomics. Using this technique, we identify a variety of proteins present on the surface of PCN, including all previously described PCN surface proteins. Identification of known surface coat proteins using these methods demonstrates the viability of the process for isolation of novel surface coat proteins. Subsequent analysis confirmed that the genes encoding seven of the novel proteins were expressed in the hypodermis. This work provides a technique for study of surface proteins in a wide range of nematodes and expands our knowledge of the surface proteome of PCN.

scholarly journals Erythrocyte entry by malarial parasites. A moving junction between erythrocyte and parasite

1978 ◽  
Vol 77 (1) ◽  
pp. 72-82 ◽  
Author(s):  
M Aikawa ◽  
LH Miller ◽  
J Johnson ◽  
J Rabbege
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Erythrocyte Membrane ◽  
Plasmodium Knowlesi ◽  
Parasitophorous Vacuole ◽  
Initial Contact ◽  
Surface Coat ◽  
Iris Diaphragm ◽  
Erythrocyte Surface

Invasion of erythrocytes by merozoites of the monkey malaria, Plasmodium knowlesi, was investigated by electron microscopy. The apical end of the merozoite makes initial contact with the erythrocyte, creating a small depression in the erythrocyte membrane. The area of the erythrocyte membrane to which the merozoite is attached becomes thickened and forms a junction with the plasma membrane of the merozoite. As the merozoite enters the invagination in the erythrocyte surface, the junction, which is in the form of a circumferential zone of attachment between the erythrocyte and merozoite, moves along the confronted membranes to maintain its position at the orifice of the invagination. When entry is completed, the orifice closes behind the parasite in the fashion of an iris diaphragm, and the junction becomes a part of the parasitophorous vacuole. The movement of the junction during invasion is an important component of the mechanism by which the merozoite enters the erythrocyte. The extracellular merozoite is covered with a prominent surface coat. During invasion, this coat appears to be absent from the portion of the merozoite within the erythrocyte invagination, but the density of the surface coat outside the invagination (beyond the junction) is unaltered.

scholarly journals Regional differentiation of the sperm surface as studied with 125I-diiodofluorescein isothiocyanate, an impermeant reagent that allows isolation of the labeled components.

1979 ◽  
Vol 82 (3) ◽  
pp. 742-754 ◽  
Author(s):  
C A Gabel ◽  
E M Eddy ◽  
B M Shapiro
Keyword(s):  
Sea Urchin ◽  
Specific Activity ◽  
High Specific Activity ◽  
Fluorescein Isothiocyanate ◽  
Surface Proteins ◽  
Regional Differentiation ◽  
Specific Cell ◽  
Sperm Surface ◽  
Erythrocyte Surface ◽  
Triton X

The regional differentiation of the sperm surface has been studied with the aid of a novel covalent labeling technique that permits concurrent cytological, biochemical, and immunological analyses. For these studies isothiocyanate derivatives of fluorescein (FITC) and diiodofluorescein (IFC) were employed: the latter can be prepared with radioiodine to high specific activity (125IFC) and is an impermeant reagent for the erythrocyte surface. Sperm of sea urchin (Strongylocentrotus purpuratus), medaka )Oryzias latipes), and golden hamster bind the fluorescent chromophores with a nonuniform distribution, most of the fluorescence being associated with the midpiece. The radioactive derivative 125IFC permits an analysis of the proteins that are responsible for most of the binding. Additionally, 125 IFC-labeled sperm are capable of fertilizing eggs, as assessed by autoradiography. That IFC labels the surface of the sperm was inferred from the following: (a) the labeling of the surfaces of other cells by fluorescein isothiocyanate and its derivatives; (b) the agglutination of labeled sperm by antibodies directed against IFC; (c) the use of peroxidase-dependent immunocytochemical reaction using anti-IFC antibodies, with analysis by electron microscopy; and (d) extraction of labeled sea urchin sperm with Triton X-100 under conditions that preferentially solubilize the plasma membrane. The antiserum directed against IFC was used to isolate the labeled surface components from Triton X-100 extracts of whole sperm, by immunoprecipitation, with Staphylococcus-A protein serving as a coprecipitant. The results support previous data showing that the sperm surface is a heterogeneous mosaic of restricted domains, one notable zone being the midpiece, where common molecular properties may be shared by sperm with distinctly different morphologies. In addition, IFC-mediated covalent alteration of specific cell surface proteins may be used to label, to identify, and, with the use of anti-IFC antibodies, to isolate such proteins from other cellular constituents.

scholarly journals A new method for the capture of surface proteins in Plasmodium falciparum parasitized erythrocyte

2012 ◽  
Vol 6 (06) ◽  
pp. 536-541 ◽  
Author(s):  
Emanuela Ferru ◽  
Anntonella Pantaleo ◽  
Francesco Turrini
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Surface ◽  
Electrophoretic Analysis ◽  
Cytoskeletal Proteins ◽  
Surface Proteins ◽  
New Method ◽  
Major Drawback ◽  
Rbc Membrane ◽  
Wide Range ◽  
Erythrocyte Surface

Introduction: We propose a new method for the selective labeling, isolation and electrophoretic analysis of the Plasmodium falciparum protein exposed on the erythrocyte cell surface. Historically, membrane surface proteins have been isolated using a surface biotinylation followed by capture of biotin-conjugated protein via an avidin/streptavidin-coated solid support. The major drawback of the standard methods has been the labeling of internal proteins due to fast internalization of biotin. Methodology: To solve this problem, we used a biotin label that does not permeate through the membrane. As a further precaution to avoid the purification of non surface exposed proteins, we directly challenged whole labeled cells with avidin coated beads and then solubilized them using non ionic detergents. Results: A marked enrichment of most of the RBC membrane proteins known to face the external surface of the membrane validated the specificity of the method; furthermore, only small amounts of haemoglobin and cytoskeletal proteins were detected. A wide range of P. falciparum proteins were additionally described to be exposed on the erythrocyte surface. Some of them have been previously observed and used as vaccine candidates while a number of newly described antigens have been presently identified. Those antigens require further characterization and validation with additional methods. Conclusion: Surface proteins preparations were very reproducible and identification of proteins by mass spectrometry has been demonstrated to be feasible and effective.

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