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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes the development and use of functional immunoradiometric assays that distinguish the activity of beta-migrating endothelial-type plasminogen activator inhibitor (PAI-1) from that of placental-type plasminogen activator inhibitor (PAI-2). These assays are based upon the binding of PAI-1 and PAI-2 to immobilized single-chain tissue-type plasminogen activator (tPA) and to immobilized urokinase (UK), respectively. The extent of binding of each PAI is quantified by incubating the PAI-PA complex first with rabbit antiserum specific for the individual PAI and then with 125I-labeled goat antirabbit IgG. In control experiments, the assays were shown to be sensitive, dose-dependent over a wide range, and specific for each PAI. These assays were employed to establish the PAI profile of a variety of human cells. Neither PAI-1 nor PAI-2 could be detected in Bowes melanoma cells or in a renal adenocarcinoma cell line (ACHN), while the histiocytic lymphoma cell (U-937) produced only PAI-2. Five cell lines, including two that were previously shown to contain one or the other PAI (e.g., umbilical vein endothelial cells and a fibrosarcoma cell line, HT-1080) in fact contained both PAIs. The cells containing both PAIs were studied in more detail. In each case, SDS treatment of CM was shown to enhance PAI-1 activity (by converting the latent form of this inhibitor into its active form) and to destroy PAI-2 activity. Various compounds including interleukin 1, dexamethasone, and phorbol myristate acetate were found to selectively influence the cellular production of one PAI without concomitantly affecting the production of the other, suggesting that the synthesis of these inhibitors is not coordinately regulated.
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PMID:Detection of both type 1 and type 2 plasminogen activator inhibitors in human cells. 325 67

An LPS-stimulated, human monocyte cDNA library was screened for stimulation-specific clones. One clone (pcD-1214) contained a 1.9-kb pair insert that hybridized to a 2,000-nucleotide mRNA expressed by peripheral blood monocytes, the histiocytic lymphoma cell line U937, and umbilical cord endothelial cells. The 415-amino-acid precursor polypeptide predicted from the cDNA (46,596 molecular weight) has a putative 22-residue signal peptide and approximately 35% homology with members of the serine protease inhibitor (Serpin) superfamily. On the basis of amino acid homology and alignment of COOH-terminal residues within the Serpin-reactive center, the clone pcD-1214 was identified as coding for an Arg-Serpin. Southern blot analysis of human-mouse somatic cell hybrid DNA locates the Arg-Serpin gene on human chromosome 18. A perfect match between amino acid residues 347-376 in this Arg-Serpin and the published sequence of a 30-residue, tryptic peptide from the COOH-terminus of a monocyte plasminogen activator-inhibitor (PAI-2), strongly suggests that the Arg-Serpin encoded by pcD-1214 is PAI-2.
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PMID:Human monocyte Arg-Serpin cDNA. Sequence, chromosomal assignment, and homology to plasminogen activator-inhibitor. 349 14

A human cell line (RC-K8) that produces plasminogen activator was established from the peritoneal effusion of a patient with histiocytic lymphoma. The RC-K8 cell line grew mainly in single cell suspension and consisted of primitive cells with pleomorphic morphology. RC-K8 cells were positive for alpha-naphthyl butyrate esterase, acid phosphatase and periodic acid-Schiff stainings. Immunologic and molecular biological studies showed that RC-K8 cells reacted with monoclonal antibodies to B cell antigens (B1 and Leu12) and Ia antigen (OKIa1) and possessed immunoglobulin gene rearrangement in the absence of surface and cytoplasmic immunoglobulin. Neither Epstein-Barr virus nuclear antigen nor terminal deoxynucleotidyl transferase was detected in the cells. Chromosome analysis of RC-K8 disclosed 46 XY with complex abnormalities including t(11;14)(q23;q32). Intraperitoneal inoculation of RC-K8 cells to immunosuppressed newborn hamsters produced massive metastatic tumors in the lungs. The RC-K8 cell line will be of considerable value for the study of lymphomagenesis associated with t(11;14) and pulmonary metastasis of lymphoma cells.
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PMID:Characterization of a new human lymphoma cell line (RC-K8) with t(11;14) chromosome abnormality. 374 63

A new cell line, designated RC-K8, was established from the peritoneal effusion of a patient with histiocytic lymphoma. The RC-K8 had human male karyotype with 14q+ and was found to have B-cell (B1) and monocyte/macrophage (intracytoplasmic alpha subunit of S-100 protein) markers. A fibrin plate method demonstrated that RC-K8 cells release plasminogen activator in culture.
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PMID:Establishment of a new human lymphoma line that secretes plasminogen activator. 391 6

Urokinase-type plasminogen activator (UPA), particularly when bound to its receptor (UPAR), is thought to play a major role in local proteolytic processes, thus facilitating cell migration as may occur during angiogenesis, neointima and atherosclerotic plaque formation, and tumor cell invasion. To facilitate understanding of the need and function of the UPA/UPAR interaction in cell migration and vascular remodeling, we changed several amino acid residues in UPA so as to interfere with its interaction with its receptor. The receptor-binding domain of UPA has been localized to a region in the growth factor domain between residues 20 and 32. Since the binding of UPA to UPAR appears to be species specific, we used the differences in amino acid sequences in the growth factor domain of UPA between various species to construct a human UPA variant that does not bind to the human UPAR. We substituted Asn22 for its mouse equivalent Tyr by site-directed mutagenesis. This mutant UPA had similar plasminogen activator characteristics as wild-type UPA, including its specific activity and interaction with plasminogen activator inhibitor-1. However, no UPA/UPAR complexes could be observed in cross-linking experiments using DFP-treated 125I-labeled mutant UPA and lysates of various cells, including U937 histiocytic lymphoma cells, phorbol myristate acetate-treated human ECs, and mouse LB6 cells transfected with human UPAR cDNA. In direct binding experiments, DFP-treated 125I-labeled mutant UPA could not bind to phorbol myristate acetate-treated ECs, whereas wild-type UPA did bind. Furthermore, a 25-fold excess of wild-type UPA completely prevented the binding of DFP-treated 125I-labeled wild-type UPA to the human receptor on transfected LB6 cells, whereas an equal amount of mutant UPA had only a very small effect. In ligand blotting assays, very weak binding of mutant UPA to human UPAR could be observed. Changing Asn22 into the other amino acid residues alanine or glutamine had no effect on binding to UPAR on human ECs. The functional integrity of the growth factor domain in the non-receptor binding Asn22Tyr mutant is suggested by the fact that binding of this mutant to a murine UPAR can be restored after additional mutations in the growth factor domain, Asn27,His29,Trp30 to Arg27,Arg29,Arg30. We conclude that Asn22 and Asn27,His29,Trp30 in human UPA are key determinants in the species-specific binding of the enzyme to its receptor and that changing Asn22 into Tyr results in a UPA mutant with strongly reduced binding to UPAR.
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PMID:Binding of human urokinase-type plasminogen activator to its receptor: residues involved in species specificity and binding. 959 26