The fine structure of cell contacts in platelet aggregation

Skaer, R. J.; Emmines, J.P.; Skaer, Helen

doi:10.1016/s0022-5320(79)80040-4

Cited by 28 publications

(13 citation statements)

References 13 publications

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“…1B). All of the ten spectra taken from different platelets were qualitatively similar, the phosphorus/ calcium ratio being 1.76 as it has been reported previously (29). Potassium and oxygen were also detected.…”

Section: Elemental Analysis and Isolation Of Human Platelet Densesupporting

confidence: 85%

Human Platelet Dense Granules Contain Polyphosphate and Are Similar to Acidocalcisomes of Bacteria and Unicellular Eukaryotes

Ruiz

Lea

Oldfield

et al. 2004

Journal of Biological Chemistry

398

513

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Inorganic polyphosphate (polyP) has been identified and measured in human platelets. Millimolar levels (in terms of P i residues) of short chain polyP were found. The presence of polyP of ϳ70 -75 phosphate units was identified by 31 P NMR and by urea-polyacrylamide gel electrophoresis of platelet extracts. An analysis of human platelet dense granules, purified using metrizamide gradient centrifugation, indicated that polyP was preferentially located in these organelles. This was confirmed by visualization of polyP in the dense granules using 4,6-diamidino-2-phenylindole and by its release together with pyrophosphate and serotonin upon thrombin stimulation of intact platelets. Dense granules were also shown to contain large amounts of calcium and potassium and both bafilomycin A 1 -sensitive ATPase and pyrophosphatase activities. In agreement with these results, when human platelets were loaded with the fluorescent calcium indicator Fura-2 acetoxymethyl ester to measure their intracellular Ca and 2) the effect of ionomycin, which could not take Ca 2؉ out of acidic organelles and was more effective after alkalinization of this compartment by the previous addition of nigericin, monensin, or NH 4 Cl. All of these characteristics of the platelet dense granules, together with their known acidity and high density (both by weight and by electron microscopy), are similar to those of acidocalcisomes (volutin granules, polyP bodies) of bacteria and unicellular eukaryotes. The results suggest that acidocalcisomes have been conserved during evolution from bacteria to humans.

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Section: Elemental Analysis and Isolation Of Human Platelet Densesupporting

confidence: 85%

Human Platelet Dense Granules Contain Polyphosphate and Are Similar to Acidocalcisomes of Bacteria and Unicellular Eukaryotes

Ruiz

Lea

Oldfield

et al. 2004

Journal of Biological Chemistry

398

513

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“…Also, Kapsenberg and 1,eene (1979) described gap junctions between PHA-stimulated rabbit lymphocytes using freeze fracture but could not identify gap junctions in sections even after tannic acid treatment. On the other hand, Skaer et al, (1979) noted regions of membrane apposition in sections of aggregated platelets treated with tannic acid which were identical to gap junctions, but with freeze fracture techniques no particle aggregates resembling gap junctions were found. Skaer et al, believe these regions are not gap junctions in the usual sense but referred to them as "gap contacts."…”

Section: Discussionmentioning

confidence: 92%

Intercellular contacts between migrating blood cells and cells of the sinusoidal wall of bone marrow. An ultrastructural study using tannic acid

Campbell

1982

Anat. Rec.

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The migration of blood cells across the sinusoidal wall of murine bone marrow was studied following fixation with tannic acid-glutaraldehyde. Electron microscopic examination showed regions of close membrane apposition (referred to in this study as "intercellular contacts") between migrating blood cells and cells of the sinusoidal wall (adventitial and endothelial cells). Ultrastructurally the intercellular contacts are pentalaminar structures resembling gap junctions of other organs after tannic-acid fixation. The possibility that these contacts are regions of intercellular communication and/or sites of membrane attachment utilized for locomotion of the migrating blood cells is discussed.

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“…The contacts between the platelet surface and fibrin strands in retracting clots were observed across a ϳ15-nm space established by the structures that initially were called "stubs" and presumably represent integrins (46,47). In contrast, the interplatelet bridges in aggregating platelets span the space of ϳ50 nm (48,49). Another distinction between platelet-fibrin and platelet-fibrinogen interactions is their sensitivity to EDTA: i.e.…”

Section: Discussionmentioning

confidence: 99%

The Interaction of Integrin αIIbβ3 with Fibrin Occurs through Multiple Binding Sites in the αIIb β-Propeller Domain

Podolnikova

Yakovlev

Yakubenko

et al. 2014

Journal of Biological Chemistry

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Background: During thrombus formation, platelet integrin ␣ IIb ␤ 3 binds fibrin; however, the mechanism of this interaction is unclear. Results: Mutations of discontinuous negatively charged and aromatic residues in the ␣ IIb ␤-propeller domain impair fibrin clot retraction and cell adhesion. Conclusion: Integrin ␣ IIb ␤ 3 has multiple binding sites for fibrin. Significance: Uncovered recognition specificity of ␣ IIb ␤ 3 for fibrin may be used to select inhibitors of this interaction.

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The fine structure of cell contacts in platelet aggregation

Cited by 28 publications

References 13 publications

Human Platelet Dense Granules Contain Polyphosphate and Are Similar to Acidocalcisomes of Bacteria and Unicellular Eukaryotes

Human Platelet Dense Granules Contain Polyphosphate and Are Similar to Acidocalcisomes of Bacteria and Unicellular Eukaryotes

Intercellular contacts between migrating blood cells and cells of the sinusoidal wall of bone marrow. An ultrastructural study using tannic acid

The Interaction of Integrin αIIbβ3 with Fibrin Occurs through Multiple Binding Sites in the αIIb β-Propeller Domain

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