Platelet Glycoproteins in Platelet Aggregation

1979 ◽  
Author(s):  
David R. Phillips ◽  
Lisa K. Jennings ◽  
Harold H. Edwards
Keyword(s):  
Membrane Surface ◽  
Direct Interaction ◽  
Protein Composition ◽  
Actin Binding ◽  
Membrane Glycoproteins ◽  
Dense Cores ◽  
Insoluble Material ◽  
Filamentous Material ◽  
Membrane Components ◽  
Triton X

Thrombin stimulation alters the membrane surface of platelets so that specific components on the membrane surface interact. To identify such “aggregation factors”, tne exposed membrane proteins of washed platelets were labeled by lactoperoxidase-catalyzed iodination and tested for their association with cytoskeletal structures. Control, thrombin-stimulated (TS; nM thrombin in mM EDTA to prevent aggregation) and thrombin aggregated (TA; 2 mM Ca++) platelets were treated with 1% Triton X-100. The insoluble material (isolated by centrifugation) from TS platelets, but not unstimulated platelets, had clusters of filamentous material with dense cores about 1 μ in diameter. Each cluster appeared to arise from one platelet and contained proteins with the Mr of actin actin-binding protein and myosin plus a 56K and 90K protein. Triton extraction of TA platelets produced an insoluble material with a similar protein composition as that from TS platelets; however, the filamentous clusters remained- aggregration, indicating tnat membrane components which aggregate platelets were still present. Analysis of iodinated membrane components revealed that all were solubilized by Triton from control and TS platelets while two glycoproteins, termed IIb and III, remained with the filamentous material from TA platelets. This and the observation that platelets lacking IIb and III cannot aggregate [JCI. 60: 535 (1977)], indicate that one or both of these membrane glycoproteins are involved in the direct Interaction of platelets during aggregation.

scholarly journals Identification of membrane proteins mediating the interaction of human platelets

1980 ◽  
Vol 86 (1) ◽  
pp. 77-86 ◽  
Author(s):  
D Phillips ◽  
L Jennings ◽  
H Edwards
Keyword(s):  
Actin Filaments ◽  
Binding Protein ◽  
Membrane Surface ◽  
Direct Interaction ◽  
Cytoskeletal Proteins ◽  
Actin Binding ◽  
Insoluble Residue ◽  
Membrane Glycoproteins ◽  
Actin Binding Protein ◽  
Activated Platelets

Membrane glycoproteins that mediate platelet-platelet interactions were investigated by identifying those associated with the cytoskeletal structures from aggregated platelets. The cytoskeletal structures from washed platelets, thrombin-activated platelets (platelets incubated with thrombin in the presence of mM EDTA to prevent aggregation) and thrombin- aggregated platelets (platelets activated in the presence of mM Ca(++) were prepared by first treating platelet suspensions with 1 percent Triton X-100 and 5 mM EGTA and then isolating the insoluble residue by centrifugation. The readily identifiable structures in electron micrographs of the residue from washed platelets had the shape and dimensions of actin filaments. Analysis of this residue from washed platelets had the shape and dimensions of actin filaments. Analysis of this residue by SDS gel electrophoresis showed that it consisted primarily of three proteins: actin (mol wt = 43,000), myosin (mol wt = 200,000) and a high molecular weight polypeptide (mol wt = 255,000) which had properties indentical to actin-binding protein (filamin). When platelets are activated with thrombin in the presence of EDTA to prevent aggregation, there was a marked increase in the amount of insoluble precipitate in the subsequent Triton extraction. Transmission electron microscopy showed that this residue not only contained the random array of actin filaments as seen above, but also organized structures from individual platelets which appeared as balls of electron-dense filamentous material approximately 1mum in diameter. SDS polyacrylamide gel analysis of the Triton residue of activated platelets showed that this preparation contained more actin, myosin and actin-binding protein than that from washed platelets plus polypeptides with mol wt of 56,000 and 90,000 and other minor polypeptides. Thus, thrombin activation appeared to increase polymerization of actin in association with other cytoskeletal proteins into structures that are observable after Triton extraction. The cytoskeletal structures from thrombin-aggregated platelets were similar to those from thrombin-activated platelets, except that the structural elements from individual platelets remained aggregated rather than randomly dispersed in the actin filaments. This suggested that the membrane components that mediate the direct interaction of platelets were in Triton residue from aggregated platelets. Only a small percentage of the membrane surface proteins and glycoproteins were found in the cytoskeletal structures from either washed platelets or thrombin-activated platelets. In contrast, the aggregated cytoskeletal structures from thrombin-aggregated platelets contained membrane glycoproteins IIb (26 percent of the total in pre-extracted platelets) and III (14 percent), suggesting that one or both of these glycoproteins participate in the direct interaction of platelets during aggregation.

scholarly journals Cell-surface attachment of pedestal-forming enteropathogenicE. coliinduces a clustering of raft components and a recruitment of annexin 2

2002 ◽  
Vol 115 (1) ◽  
pp. 91-98
Author(s):  
Nicole Zobiack ◽  
Ursula Rescher ◽  
Sven Laarmann ◽  
Silke Michgehl ◽  
M. Alexander Schmidt ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Surface ◽  
Actin Binding ◽  
Surface Attachment ◽  
Glycosyl Phosphatidylinositol ◽  
Annexin 2 ◽  
Endosomal Membranes ◽  
Membrane Components ◽  
Functional Receptor ◽  
Pedestal Formation

Annexin 2 is a Ca2+-regulated membrane- and F-actin-binding protein implicated in the stabilization or regulation of membrane/cytoskeleton contacts, or both, at the plasma membrane and at early endosomal membranes. To analyze the dynamic nature of such action we investigated whether annexin 2 could be found at sites of localized actin rearrangements occurring at the plasma membrane of HeLa cells infected with noninvading enteropathogenic Escherichia coli (EPEC). We show that adherent EPEC microcolonies, which are known to induce the formation of actin-rich pedestals beneath them, specifically recruit annexin 2 to the sites of their attachment. Mutant EPEC (EPECtir), which lack a functional receptor for intimate attachment (Tir, translocated intimin receptor) and which fail to produce full pedestal formation, are still capable of recruiting annexin 2 to the bacterial contact sites. Accumulation of annexin 2 at sites of EPEC or EPECtir attachment is accompanied by a recruitment of the annexin 2 protein ligand S100A10. EPEC and EPECtir attachment also induces a concentration of cholesterol and glycosyl phosphatidylinositol-anchored proteins at sites of bacterial contact. This indicates that membrane components present in rafts or raft-like microdomains are clustered upon EPEC adherence and that annexin 2 is recruited to the cytoplasmic membrane surface of such clusters, possibly stabilizing raft patches and their linkage to the actin cytoskeleton beneath adhering EPEC.

scholarly journals Solubilization and fractionation of glycoproteins and glycolipids of KB cell membranes

1974 ◽  
Vol 140 (3) ◽  
pp. 469-478 ◽  
Author(s):  
Terry D. Butters ◽  
R. Colin Hughes
Keyword(s):  
Plasma Membranes ◽  
Sodium Dodecyl ◽  
Deae Cellulose ◽  
Adenovirus Type ◽  
Insoluble Residue ◽  
Membrane Glycoproteins ◽  
Low Concentrations ◽  
Ceramide Trihexoside ◽  
Membrane Components ◽  
Triton X

1. A fraction enriched in plasma membranes of human tumour KB cell line, a permissive cell for adenovirus type 5, was obtained. 2. Electrophoresis of the membranes in polyacrylamide gels with buffers containing sodium dodecyl sulphate showed that the membranes after reduction with 2-mercaptoethanol contained over 20 polypeptide species. Three polypeptides were glycosylated and had apparent mol.wts. of 92000, 72000 and 62000. 3. The glycoproteins and the specific receptors responsible for adenovirus adsorption to the membranes were readily extracted into solutions containing low concentrations of Triton X-100. Glycolipids and proteins were also made soluble. A membranous residue obtained after Triton X-100 extraction was enriched in several proteins that appeared to consist of polypeptides of lower molecular weight than the average of KB membrane polypeptides. 4. Sphingomyelin, cholesterol and triglycerides were similarly concentrated in the insoluble residue remaining after successive extractions of KB membranes with Triton X-100. Further, ceramide trihexoside was significantly less easily extracted from KB membranes than lactosyl ceramide. 5. The differences noted in the ease of extraction of membrane components are discussed. 6. The components of membranes made soluble by detergent extraction and containing the large part of the KB membrane glycoproteins were subjected to chromatography on Sepharose 6B and DEAE-cellulose and to isoelectric focusing in the presence of buffers containing Triton X-100. In general, the degree of separation into fractions enriched in individual glycoproteins was disappointing. Possible reasons for the poor fractionation of membrane components by chromatographic systems conveniently used for purification of proteins and glycoproteins of non-membranous origin are briefly discussed.

scholarly journals The relationship of detergent-solubilization plasma-membrane components of rabbit alveolar macrophages to an isolated inhibitor of phagocytosis

1979 ◽  
Vol 179 (2) ◽  
pp. 305-314 ◽  
Author(s):  
R S Pratt ◽  
G M Cook
Keyword(s):  
Plasma Membrane ◽  
Alveolar Macrophages ◽  
Membrane Fraction ◽  
Lung Lavage ◽  
Membrane Glycoproteins ◽  
Rabbit Lung ◽  
Membrane Components ◽  
Triton X ◽  
Relationship Of ◽  
The Relationship

1. A plasma-membrane fraction prepared from rabbit alveolar macrophages by hyposmotic borate lysis is described. 2. Rabbit lung lavages, containing a glycoprotein inhibitor of phagocytosis, may be fractionated by preparative isoelectric focusing in the presence of Triton X-100. 3. Chemical analysis indicates that the glycoproteins of the lung lavage contain sialic acid, fucose, mannose, galactose, hexosamine and appreciable quantities of glucose. 4. The relationship of macrophage membrane glycoproteins, solubilized with Triton X-100 in the presence of borate, to the lung lavage glycoproteins is demonstrated immunoelectrophoretically.

Agonist-induced Actin Polymerization Is Required for the Irreversibility of Platelet Aggregation

1996 ◽  
Vol 76 (03) ◽  
pp. 444-449 ◽  
Author(s):  
Mauro Torti ◽  
Enrico Tolnai Festetics ◽  
Alessandro Bertoni ◽  
Fabiola Sinigaglia ◽  
Cesare Balduini
Keyword(s):  
Platelet Aggregation ◽  
Actin Polymerization ◽  
Chelating Agent ◽  
Cytochalasin D ◽  
Actin Binding ◽  
Fibrinogen Binding ◽  
Insoluble Material ◽  
Platelet Disaggregation ◽  
Dependent Inhibition ◽  
Triton X

SummaryCytochalasin D was used to investigate the role of intracellular cyto-skeleton in the stabilization of platelet aggregation induced by strong platelet agonists. Incubation of gel-filtered platelets with increasing concentrations of cytochalasin D resulted in a dose-dependent inhibition of actin polymerization and association of actin-binding proteins with the Triton X-100-insoluble material induced by the thromboxane analogue, U46619, and the thrombin receptor activating peptide, TRAP. The same concentrations of cytochalasin D did not significantly inhibit platelet aggregation promoted by the two agonists. The addition of the chelating agent EDTA to fully aggregated platelets, that had been treated with cytochalasin D, resulted in the rapid and almost complete disaggregation. EDTA did not cause disaggregation of control, solvent-treated, aggregated platelets. The degree of platelet disaggregation induced by EDTA was dependent on the dose of cytochalasin D used, and was correlated with the inhibition of the cytoskeletal reorganization. Aggregation of cytochalasin D-treated platelets stimulated with U46619 or TRAP was also reverted by the addition of the tetrapeptide RGDS or the fibrinogen y-chain dodecapeptide, which competitively interfere with fibrinogen binding to the glycoprotein Ilb-IIIa complex. These results indicate that the intracellular cytoskeleton plays an essential role in the stabilization of the fibrinogen-platelet interaction, and is necessary for the irreversibility of platelet aggregation induced by strong agonists.

Immunoelectrophoretic Analysis of Membrane Glycoproteins in Cultured Human Endothelial Cells

1990 ◽  
Vol 63 (02) ◽  
pp. 303-311
Author(s):  
Tone Børsum
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Rabbit Antiserum ◽  
Platelet Glycoprotein ◽  
Membrane Glycoproteins ◽  
Human Endothelial Cells ◽  
Immunoelectrophoretic Analysis ◽  
Glycoprotein Complex ◽  
Crossed Immunoelectrophoresis ◽  
Triton X

SummaryHuman endothelial cells isolated from umbilical cordswere solubilized in Triton X-100 and examined by crossedimmunoelec-trophoresis using rabbit antiserum against endothelial cells. Endogenous labelling of the endothelialcell proteins with 14Cmannose followed by crossed immunoelectrophoresis and autoradiography revealed about 10 immunoprecipitates. Four of these endothelial cell glycoproteins were labelled by lactoperoxidase catalyzed iodination and thus were surface located. Three of the surface located glycoproteins showed reduced electrophoretic mobility after incubation of the endothelial cells with neuraminidase and were therefore sialoglycoproteins. Amphiphilicity of endothelial cell glycoproteins was studied by crossed hydrophobic interaction immunoelectrophoresis with phenyl-Sepharose in the intermediate gel. Amphiphilic proteins also show increasing electrophoretic migration velocity with decreasing concentration of Triton X-100 in the first dimension gels. Five of the endothelial cell glycoproteins were shown to be amphiphilic using these two techniques.Two monoclonal antibodies against the platelet glycoprotein complex Ilb-IIIa and glycoprotein IlIa, respectively, reacted with the same precipitate of endothelial cells. When a polyclonal antibody against the platelet glycoprotein complex Ilb-IIIa was incorporated into the intermediate gel the position of two endothelial cell precipitates were lowered. One of these was a sialoglycoprotein.

Binding of Human Platelet Glycoprotein lb and Actin to Fragments of Actin-Binding Protein

1992 ◽  
Vol 67 (02) ◽  
pp. 252-257 ◽  
Author(s):  
Anne M Aakhus ◽  
J Michael Wilkinson ◽  
Nils Olav Solum
Keyword(s):  
Actin Filaments ◽  
High Speed ◽  
Binding Protein ◽  
Protein A ◽  
Actin Binding ◽  
Platelet Glycoprotein ◽  
Actin Binding Protein ◽  
Crossed Immunoelectrophoresis ◽  
Triton X ◽  
Calpain Inhibitors

SummaryActin-binding protein (ABP) is degraded into fragments of 190 and 90 kDa by calpain. A monoclonal antibody (MAb TI10) against the 90 kDa fragment of ABP coprecipitated with the glycoprotein lb (GP lb) peak observed on crossed immunoelectrophoresis of Triton X-100 extracts of platelets prepared without calpain inhibitors. MAb PM6/317 against the 190 kDa fragment was not coprecipitated with the GP lb peak under such conditions. The 90 kDa fragment was adsorbed on protein A agarose from extracts that had been preincubated with antibodies to GP lb. This supports the idea that the GP Ib-ABP interaction resides in the 90 kDa region of ABP. GP lb was sedimented with the Triton-insoluble actin filaments in trace amounts only, and only after high speed centrifugation (100,000 × g, 3 h). Both the 190 kDa and the 90 kDa fragments of ABP were sedimented with the Triton-insoluble actin filaments.

scholarly journals Calpain activity in patients with thrombotic thrombocytopenic purpura is associated with platelet microparticles

Blood ◽  
1992 ◽  
Vol 80 (9) ◽  
pp. 2246-2251 ◽  
Author(s):  
JG Kelton ◽  
TE Warkentin ◽  
CP Hayward ◽  
WG Murphy ◽  
JC Moore
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Membrane Association ◽  
Membrane Glycoproteins ◽  
Calpain Activity ◽  
Thrombocytopenic Purpura ◽  
Calcium Dependent ◽  
Active Protease ◽  
Triton X ◽  
Platelet Microparticles

Abstract Thrombotic thrombocytopenic purpura (TTP) is characterized by thrombocytopenia and disseminated platelet thrombi throughout the microvasculature. Studies by our group have demonstrated calcium- dependent proteolytic activity (calpain) that is no longer detectable in the serum of patients with acute TTP after their recovery. The purpose of this study was to investigate if the protease activity of TTP was detectable in plasma and, therefore, not an in vitro phenomenon secondary to the formation of serum. Additionally, we looked for evidence of membrane association of the active protease in the patients' samples, which would explain the persistence of its activity in the presence of plasma inhibitors. Acute TTP samples, both serum and plasma, were collected from 10 patients with TTP. Calpain was measured using bioassays for enzyme activity and also by detection of the protein using immunoblotting with an anticalpain monoclonal antibody (MoAb). In all instances, calpain could be detected both functionally and antigenically in the acute TTP sera and plasma. No calpain activity could be detected in any of the controls, although antigenic calpain was detectable in one sample from a patient who had undergone cardiopulmonary bypass surgery. To investigate whether the calpain was associated with microparticles in the plasma, the TTP plasma samples were ultrafiltered and ultracentrifuged. Activity was not lost by passage across a 0.2-micron filter but was detectable only in the pellet following ultracentrifugation. Membrane association of the calpain in the microparticles also was demonstrated using solubilization with Triton X-100. Immunoprecipitation studies demonstrated that the calpain activity could be removed by MoAbs against platelet membrane glycoproteins (IX and IIb/IIa) but not by a MoAb against red blood cell membrane glycophorin. These studies indicate that active calpain is associated with platelet microparticles in plasma from patients with TTP.

Polarization and interaction of adhesion molecules P-selectin glycoprotein ligand 1 and intercellular adhesion molecule 3 with moesin and ezrin in myeloid cells

Blood ◽  
2000 ◽  
Vol 95 (7) ◽  
pp. 2413-2419 ◽  
Author(s):  
José L. Alonso-Lebrero ◽  
Juan M. Serrador ◽  
Carmen Domı́nguez-Jiménez ◽  
Olga Barreiro ◽  
Alfonso Luque ◽  
...  
Keyword(s):  
Adhesion Molecules ◽  
Adhesion Molecule ◽  
Direct Interaction ◽  
Intercellular Adhesion ◽  
Actin Binding ◽  
Intercellular Adhesion Molecule ◽  
Human Neutrophils ◽  
Binding Assays ◽  
Glutathione S Transferase ◽  
Amino Terminal

Abstract In response to the chemoattractants interleukin 8, C5a,N-formyl-methionyl-leucyl-phenylalanine, and interleukin 15, adhesion molecules P-selectin glycoprotein ligand 1 (PSGL-1), intercellular adhesion molecule 3 (ICAM-3), CD43, and CD44 are redistributed to a newly formed uropod in human neutrophils. The adhesion molecules PSGL-1 and ICAM-3 were found to colocalize with the cytoskeletal protein moesin in the uropod of stimulated neutrophils. Interaction of PSGL-1 with moesin was shown in HL-60 cell lysates by isolating a complex with glutathione S-transferase fusions of the cytoplasmic domain of PSGL-1. Bands of 78- and 81-kd were identified as moesin and ezrin by Western blot analysis. ICAM-3 and moesin also coeluted from neutrophil lysates with an anti-ICAM-3 immunoaffinity assay. Direct interaction of the cytoplasmic domains of ICAM-3 and PSGL-1 with the amino-terminal domain of recombinant moesin was demonstrated by protein-protein binding assays. These results suggest that the redistribution of PSGL-1 and its association with intracellular molecules, including the ezrin-radixin-moesin actin-binding proteins, regulate functions mediated by PSGL-1 in leukocytes stimulated by chemoattractants.

scholarly journals Epithelial structure revealed by chemical dissection and unembedded electron microscopy.

1984 ◽  
Vol 99 (1) ◽  
pp. 203s-208s ◽  
Author(s):  
E G Fey ◽  
D G Capco ◽  
G Krochmalnic ◽  
S Penman
Keyword(s):  
Nuclear Matrix ◽  
Intermediate Filament ◽  
Protein Composition ◽  
Intact Cells ◽  
Thin Sections ◽  
Transmission Electron ◽  
Kidney Epithelial Cell ◽  
Epithelial Structure ◽  
Triton X ◽  
Whole Mounts

Cytoskeletal structures obtained after extraction of Madin-Darby canine kidney epithelial cell monolayers with Triton X-100 were examined in transmission electron micrographs of cell whole mounts and unembedded thick sections. The cytoskeleton, an ordered structure consisting of a peripheral plasma lamina, a complex network of filaments, and chromatin-containing nuclei, was revealed after extraction of intact cells with a nearly physiological buffer containing Triton X-100. The cytoskeleton was further fractionated by extraction with (NH4)2SO4, which left a structure enriched in intermediate filaments and desmosomes around the nuclei. A further digestion with nuclease and elution with (NH4)2SO4 removed the chromatin. The stable structure that remained after this procedure retained much of the epithelial morphology and contained essentially all of the cytokeratin filaments and desmosomes and the chromatin-depleted nuclear matrices. This structural network may serve as a scaffold for epithelial organization. The cytoskeleton and the underlying nuclear matrix intermediate filament scaffold, when examined in both conventional embedded thin sections and in unembedded whole mounts and thick sections, showed the retention of many of the detailed morphological aspects of the intact cells, which suggests a structural continuum linking the nuclear matrix, the intermediate filament network, and the intercellular desmosomal junctions. Most importantly, the protein composition of each of the four fractions obtained by this sequential procedure was essentially unique. Thus, the proteins constituting the soluble fraction, the cytoskeleton, the chromatin fraction, and the underlying nuclear matrix-intermediate filament scaffold are biochemically distinct.

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