| Binding of tissue plasminogen activator to human monocytes and monocytoid cells. | |
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MedLine Citation:
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PMID: 1932747 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Monocytes and monocytoid cell lines previously have been shown to express receptors for plasminogen and urokinase (u-PA). In the present study, the monocytoid cell lines, U937 and THP-1, are shown to bind tissue plasminogen activator (t-PA) in a specific, saturable, and reversible manner. These cells bound t-PA with low affinity (kd = 0.67 to 0.97 mumol/L) and high capacity (0.71 to 3.3 x 10(6) receptors/cell). Human peripheral blood monocytes bound t-PA with a kd (0.9 mumol/L) similar to that of the monocytoid cells but with a lower capacity (0.17 x 10(6) sites/cell). These binding parameters also were similar to the low-affinity interaction of t-PA with endothelial cells as measured with the cells in suspension (kd = 0.73 mumol/L and 1.1 x 10(6) sites/cell). Lysine analogues and active or diisopropylfluorophosphate-inactivated u-PA inhibited t-PA binding to monocytes, monocytoid cells, and endothelial cells with similar IC50 (concentration producing 50% inhibition) values, suggesting that the same recognition specificity mediates t-PA binding to all of these cell types. The existence of a high-affinity binding site for t-PA on monocytoid cells was also explored in detail. Unlike endothelial cells where plasminogen activator inhibitor-1 has been implicated in mediating a high-affinity interaction of t-PA with the cells, no evidence for a role of this inhibitor in ligand binding to the monocytoid cells was found. Furthermore, using both high and low 125I-t-PA concentrations, competition analyses with lysine analogues or u-PA, or treatment of the cells with carboxypeptidase B, failed to indicate the presence of distinguishable classes of t-PA binding sites. In sum, low-affinity receptors for t-PA are expressed at high density on monocytes and monocytoid cells, identifying a new element in the fibrinolytic arsenal of these cells. |
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Authors:
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J Felez; C J Chanquia; E G Levin; L A Miles; E F Plow |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Blood Volume: 78 ISSN: 0006-4971 ISO Abbreviation: Blood Publication Date: 1991 Nov |
Date Detail:
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Created Date: 1991-12-02 Completed Date: 1991-12-02 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 7603509 Medline TA: Blood Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 2318-27 Citation Subset: AIM; IM |
Affiliation:
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Committee on Vascular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Arginine
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pharmacology Binding Sites Cell Line Endothelium, Vascular / metabolism Erythrocytes / metabolism Humans Isoflurophate / pharmacology Kinetics Lysine / analogs & derivatives, pharmacology Monocytes / metabolism* Neutrophils / metabolism Recombinant Proteins / metabolism Tissue Plasminogen Activator / metabolism* Umbilical Veins Urokinase-Type Plasminogen Activator / pharmacology |
| Grant Support | |
ID/Acronym/Agency:
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CA41085/CA/NCI NIH HHS; HL17964/HL/NHLBI NIH HHS; HL45934/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Recombinant Proteins; 55-91-4/Isoflurophate; 56-87-1/Lysine; 74-79-3/Arginine; EC 3.4.21.68/Tissue Plasminogen Activator; EC 3.4.21.73/Urokinase-Type Plasminogen Activator |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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