Characterization of Cellular Binding Sites and Interactive Regions within Reactants Required for Enhancement of Plasminogen Activation by tPA on the Surface of Leukocytic Cells

Félez, Jordi; Miles, Lindsey A.; Fàbregas, Pere; Jardı́, Mercè; Plow, Edward F.; Lijnen, Roger

doi:10.1055/s-0038-1650625

Cited by 92 publications

(101 citation statements)

References 34 publications

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“…These cells have previously been characterized for binding of plasminogen, uPA and tPA (8,9,31,32). In the present detailed study, the levels of stimulation with fulllength glycosylated tPA were up to 30 -80-fold, which is as good as or better than observed in previous studies with cells or isolated receptors or heparin or fibrinogen fragments (5, 21).…”

Section: Discussionsupporting

confidence: 62%

“…For example, the tPA receptor annexin II, which binds tPA with a K d of 48 nM, is capable of producing modest stimulation of enzyme activity (Ͻ10-fold) in vitro (7). Monocytes and monocytoid cells have been studied and found to bind tPA with a low affinity, but high capacity, and are able to stimulate tPA enzyme activity up to around 20-fold (8,9). Other receptors on liver cells have also been investigated in an attempt to understand the structural features of tPA, both protein and carbohydrate, involved in receptor binding and responsible for its short in vivo half-life and rapid clearance from the circulation when tPA is administered as a thrombolytic agent (10).…”

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confidence: 99%

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Regulation of Tissue Plasminogen Activator Activity by Cells

Sinniger

Merton

Fàbregas

et al. 1999

Journal of Biological Chemistry

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A number of cell types have previously been shown to bind tissue plasminogen activator (tPA), which in some cases can remain active on the cell surface resulting in enhanced plasminogen activation kinetics. We have investigated several cultured cell lines, U937, THP1, K562, Molt4, and Nalm6 and shown that they bind both tPA and plasminogen and are able to act as promoters of plasminogen activation in kinetic assays. To understand what structural features of tPA are involved in cell surface interactions, we performed kinetic assays with a range of tPA domain deletion mutants consisting of fulllength glycosylated and nonglycosylated tPA (F-G-K1-K2-P), ⌬FtPA (G-K1-K2-P), K2-P tPA (BM 06.022 or Reteplase), and protease domain (P). Deletion variants were made in Escherichia coli and were nonglycosylated. Plasminogen activation rates were compared with and without cells, over a range of cell densities at physiological tPA concentrations, and produced maximum levels of stimulation up to 80-fold with full-length, glycosylated tPA. Stimulation for nonglycosylated full-length tPA dropped to 45-60% of this value. Loss of N-terminal domains as in ⌬FtPA and K2P resulted in a further loss of stimulation to 15-30% of the full-length glycosylated value. The protease domain alone was stimulated at very low levels of up to 2-fold. Thus, a number of different sites are involved in cell interactions especially within finger and kringle domains, which is similar to the regulation of tPA activity by fibrin. A model was developed to explain the mechanism of stimulation and compared with actual data collected with varying cell, plasminogen, or tPA concentrations and different tPA variants. Experimental data and model predictions were generally in good agreement and suggest that stimulation is well explained by the concentration of reactants by cells.

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Section: Discussionsupporting

confidence: 62%

mentioning

confidence: 99%

Regulation of Tissue Plasminogen Activator Activity by Cells

Sinniger

Merton

Fàbregas

et al. 1999

Journal of Biological Chemistry

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“…[26][27][28][29][30][31][32][33] Independent studies also have implicated externalized α-enolase and GAPDH on mammalian and pathogen surfaces as sites for plasminogen binding and subsequent activation by host or pathogen activities, [26][27][28]30,31,[34][35][36] and we have demonstrated that externalized glycolytic enzymes on the apoptotic cell surface, including α-enolase, also are sites for plasminogen binding. 12 Although enhanced virulence has been attributed to the presumptive augmentation in mobility through matrix or fibrin clots associated with localized plasminogen activation following binding on the pathogen surface, 37,38 no compelling physiological rationale exists for plasminogen binding on non-invasive bacteria and apoptotic cells.…”

Section: Box 1 the Repertoire Of Innate Apoptotic Immunity Early Transupporting

confidence: 57%

Exploiting death: apoptotic immunity in microbial pathogenesis

Ucker

2016

Cell Death Differ

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Innate immunity typically is responsible for initial host responses against infections. Independently, nucleated cells that die normally as part of the physiological process of homeostasis in mammals (including humans) suppress immunity. Specifically, the physiological process of cell death (apoptosis) generates cells that are recognized specifically by viable cells of all types and elicit a profound transient suppression of host immunity (termed 'innate apoptotic immunity' (IAI)). IAI appears to be important normally for the maintenance of self-tolerance and for the resolution of inflammation. In addition, pathogens are able to take advantage of IAI through a variety of distinct mechanisms, to enable their proliferation within the host and enhance pathogenicity. For example, the protist pathogen Leishmania amazonensis, at its infective stage, mimics apoptotic cells by expressing apoptotic-like protein determinants on the cell surface, triggering immunosuppression directly. In contrast, the pathogenic bacterium Listeria monocytogenes triggers cell death in host lymphocytes, relying on those apoptotic cells to suppress host immune control and facilitate bacterial expansion. Finally, although the inhibition of apoptotic cell death is a common attribute of many viruses which facilitates their extended replication, it is clear that adenoviruses also reprogram the non-apoptotic dead cells that arise subsequently to manifest apoptotic-like immunosuppressive properties. These three instances represent diverse strategies used by microbial pathogens to exploit IAI, focusing attention on the potency of this facet of host immune control. Further examination of these cases will be revealing both of varied mechanisms of pathogenesis and the processes involved in IAI control.

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“…Then 20 nM single-chain recombinant human t-PA (Genentech, South San Francisco, CA) was added. Plasmin activity (expressed as OD 405 nM) was measured after 6 min by diluting the reaction mixture 1:10 into S-2251 (DiaPharma Group, Franklin, OH) to a final concentration of 1 mM and monitoring absorbance at 405 nM as described previously (Felez et al, 1996).…”

Section: Methodsmentioning

confidence: 99%

Cell-Surface Actin Binds Plasminogen and Modulates Neurotransmitter Release from Catecholaminergic Cells

Miles¹,

Andronicos²,

Baik³

et al. 2006

J. Neurosci.

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An emerging area of research has documented a novel role for the plasminogen activation system in the regulation of neurotransmitter release. Prohormones, secreted by cells within the sympathoadrenal system, are processed by plasmin to bioactive peptides that feed back to inhibit secretagogue-stimulated release. Catecholaminergic cells of the sympathoadrenal system are prototypic prohormone-secreting cells. Processing of prohormones by plasmin is enhanced in the presence of catecholaminergic cells, and the enhancement requires binding of plasmin(ogen) to cellular receptors. Consequently, modulation of the local cellular fibrinolytic system of catecholaminergic cells results in substantial changes in catecholamine release. However, mechanisms for enhancing prohormone processing and cellsurface molecules mediating the enhancement on catecholaminergic cells have not been investigated. Here we show that plasminogen activation was enhanced Ͼ6.5-fold on catecholaminergic cells. Carboxypeptidase B treatment decreased cell-dependent plasminogen activation by ϳ90%, suggesting that the binding of plasminogen to proteins exposing C-terminal lysines on the cell surface is required to promote plasminogen activation. We identified catecholaminergic plasminogen receptors required for enhancing plasminogen activation, using a novel strategy combining targeted specific proteolysis using carboxypeptidase B with a proteomics approach using twodimensional gel electrophoresis, radioligand blotting, and tandem mass spectrometry. Two major plasminogen-binding proteins that exposed C-terminal lysines on the cell surface contained amino acid sequences corresponding to ␤/␥-actin. An anti-actin monoclonal antibody inhibited cell-dependent plasminogen activation and also enhanced nicotine-dependent catecholamine release. Our results suggest that cell-surface-expressed forms of actin bind plasminogen, thereby promoting plasminogen activation and increased prohormone processing leading to inhibition of neurotransmitter release.

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Characterization of Cellular Binding Sites and Interactive Regions within Reactants Required for Enhancement of Plasminogen Activation by tPA on the Surface of Leukocytic Cells

Cited by 92 publications

References 34 publications

Regulation of Tissue Plasminogen Activator Activity by Cells

Regulation of Tissue Plasminogen Activator Activity by Cells

Exploiting death: apoptotic immunity in microbial pathogenesis

Cell-Surface Actin Binds Plasminogen and Modulates Neurotransmitter Release from Catecholaminergic Cells

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