Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique.

Nakata, Takao; Hirokawa, Nobutaka

doi:10.1083/jcb.105.4.1771

Cited by 70 publications

(59 citation statements)

References 39 publications

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“…Such a periodic arrangement of membrane-associated filaments has also not been reportedly observed in platelets (Fox et al, , 1987Gonella and Nachmias, 1981;Jennings et al, 1981;Nachmias, 1980;Nachmias et al, 1977Nachmias et al, , 1979, but only one other study (Nakata and Hirokawa, 1987) has used quick-freezing as a means to observe the platelet cytoskeleton, and in that study the cells were fixed and treated with Triton to permeabilize the membrane and allow SI heavy meromyosin decoration of actin filaments. Hence, the membraneassociated cytoskeleton would potentially be lost.…”

Section: Discussionmentioning

confidence: 99%

Platelet membrane skeleton revealed by quick‐freeze deep‐etch

Bearer

1990

Anat. Rec.

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Actin polymerization is an essential component of platelet activation. Since actin appears to polymerize at its membrane-associated end, knowledge of the structural relationship of actin filaments to membrane is an important part of understanding that polymerization process. A membrane-associated actin-containing cytoskeleton has been described in human platelets biochemically and is composed, at least in part, by an association between glycoprotein Ib and the actin-binding protein originally isolated from macrophages. Many other actin-associated proteins with known sub-membranous localization in other systems have been found in platelets, including alpha-actinin, vinculin, and low levels of spectrin and the red cell protein Band 4.1. Because of the density of the platelet cytoplasm, the structure of the membrane-skeleton has not yet been visualized. We have used quick freeze-deep etch techniques to observe the sub-membranous cytoplasm and report visualization of a periodic, submembranous filament system not before seen in the platelet. This filamentous system was more easily observed in thrombin-stimulated platelets, but appeared to be present in resting, discoid cells as well. The filaments could also be readily observed when platelets are lysed after fixation, stained with tannic acid, and embedded for thinsectioning. This membrane cytoskeleton was composed of 9 nm thick filaments lying 15 nm apart, and 15 nm from the membrane. The filaments appeared to lie in parallel and to encircle the cell. Similar filaments could be seen associated with intracytoplasmic membrane systems in activated cells.The main function of the human blood platelet is to maintain hemostasis by plugging rents in vessel walls. To accomplish this, the freely circulating anucleate cell must recognize that a tear has occurred, and respond to it by sticking to the area of damage and to other platelets. This response involves a complicated set of events, which includes changes in the surface membrane, in cell shape, and in the polymerization state of actin. Many of these events take place on the plasma membrane. How actin and the membrane interact has been studied by a number of different investigators. In the resting discoid cell, glycoprotein Ib has been shown by immunoprecipitation to be associated with actin-binding protein, a 260 kD protein originally isolated from macrophages (Fox, 1985; Okita et al., 1985). Interaction between the actin-associated proteins, gelsolin and profilin, and phosphoinositides, metabolites of the membrane lipid, phosphatidylinositol, may be part of the mechanism mediating their interaction with actin Lassing and Lindberg, 1985) which, under activating conditions, results in the elongation of actin filaments at the membrane cytoplasmic interface. During activation the platelet membrane becomes sticky, and adhesion complexes form which are similar to those in fibroblasts that attach the cell to extracellular matrix. These adhesions also require a structural association between the HHS Public Access Autho...

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Section: Discussionmentioning

confidence: 99%

Platelet membrane skeleton revealed by quick‐freeze deep‐etch

Bearer

1990

Anat. Rec.

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“…Glomeruli were isolated by perfusing mice with Dynabeads as previously described (52) but without collagenase digestion. Glomeruli were then subjected to membrane extraction as previously described (53). Throughout the different steps a magnet was used to prevent loss of glomeruli during washes.…”

Section: Methodsmentioning

confidence: 99%

Injury-induced actin cytoskeleton reorganization in podocytes revealed by super-resolution microscopy

et al. 2017

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“…Platelets are contractile cells (1) that are activated by various chemical stimuli, such as thrombin (3,4), which results in the reorganization of the platelet cytoskeleton (5). This reorganization is driven by the energy-dependent interaction of nonmuscle myosin IIa with actin and is followed by the relocation of actin filaments to the filopodia on the periphery of the platelet (5). In addition to activating platelets, thrombin converts fibrinogen to fibrin (6)(7)(8)(9) and activates factor XIII (FXIII / FXIIIa), which catalyzes the cross-linking of fibrin (6).…”

Section: Introductionmentioning

confidence: 99%

Interplay of Platelet Contractility and Elasticity of Fibrin/Erythrocytes in Blood Clot Retraction

Tutwiler

Wang

Litvinov

et al. 2017

Biophysical Journal

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Blood clot contraction (retraction) is driven by platelet-generated forces propagated by the fibrin network and results in clot shrinkage and deformation of erythrocytes. To elucidate the mechanical nature of this process, we developed a model that combines an active contractile motor element with passive viscoelastic elements. Despite its importance for thrombosis and wound healing, clot contraction is poorly understood. This model predicts how clot contraction occurs due to active contractile platelets interacting with a viscoelastic material, rather than to the poroelastic nature of fibrin, and explains the observed dynamics of clot size, ultrastructure, and measured forces. Mechanically passive erythrocytes and fibrin are present in series and parallel to active contractile cells. This mechanical interplay induces compressive and tensile resistance, resulting in increased contractile force and a reduced extent of contraction in the presence of erythrocytes. This experimentally validated model provides the fundamental mechanical basis for understanding contraction of blood clots.

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Cytoskeletal reorganization of human platelets after stimulation revealed by the quick-freeze deep-etch technique.

Cited by 70 publications

References 39 publications

Platelet membrane skeleton revealed by quick‐freeze deep‐etch

Platelet membrane skeleton revealed by quick‐freeze deep‐etch

Injury-induced actin cytoskeleton reorganization in podocytes revealed by super-resolution microscopy

Interplay of Platelet Contractility and Elasticity of Fibrin/Erythrocytes in Blood Clot Retraction

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