Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathogenesis of Hailey-Hailey disease and Darier's disease was investigated using immunocytological and explant-tissue-culture techniques. There was breakdown of the intercellular adhesions between keratinocytes in explants from clinically uninvolved skin of patients with Hailey-Hailey disease or Darier's disease. The major desmosomal components were present in the cultures and were expressed in a punctate peripheral pattern at cell-cell contact sites, but there was diffuse staining of acantholytic cells. Plasminogen, which is expressed by basal keratinocytes in normal skin, was detected in association with suprabasal acantholytic cells in skin biopsies from these diseases. Plasminogen was reversibly displaced from the cells by 6-aminohexanoic acid, suggesting that binding is mediated by a reaction with the lysine receptor on the plasminogen molecule. Plasminogen was also detected in separating cells in explant cultures and there was cytoplasmic expression of the plasminogen activator urokinase by these cells. These abnormalities are not unique to either disease and do not account for the phenotypic differences between Darier's disease and Hailey-Hailey disease, but plasmin generation may have a role in perpetuating cell separation.
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PMID:Cell adhesion in Hailey-Hailey disease and Darier's disease: immunocytological and explant-tissue-culture studies. 175 48

Plasminogen activator (uPA) activities were determined in the tears of rabbits following mechanical (scraping) or chemical (n-heptanol) debridement and alkali burn of the central part of the corneal epithelium. All three types of injury enhanced the plasminogen activator activities in the tears. The increase in uPA activity was highest in alkali burn, lowest for n-heptanol debridement. Scraping yielded an intermediate increase in uPA activity. The maximum value in activator activity was reached at 5 hours for mechanical injury and at 24 hours for chemical injuries. uPA activity values returned to the normal range by the time of re-epithelialization for mechanical scraping and 1-3 days following re-epithelialization for heptanol debridement and alkali burn. A trend was observed between uPA activity level and the size of the wound but the correlation was not pronounced (R = 0.538).
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PMID:Tear plasminogen activators--indicators of epithelial cell destruction. The effect of scraping, n-heptanol debridement, and alkali burn of the cornea on the plasminogen activator activity of rabbit tears. 177 66

Maywood I is a dysfunctional plasminogen. It is described in a patient (W.Y.) with a reduced plasma functional activity and with a low normal antigen level. Plasminogen was isolated from the patients plasma by affinity chromatography with L-lysine-substituted Sepharose. The protein yield was 86 mg/l, which was 88% of the plasma Plg antigen level; the specific activity was 24.4 IU/mg protein compared to 28.5 IU/mg protein for the native molecule. The protein was the Glu-form determined by SDS-PAGE and by isoelectric focusing. Six major isoelectric forms were found with isoelectric points between pH's 6.40 and 5.45. Titration of the equimolar plasminogen.streptokinase complex with p-nitrophenyl-p-guanidinobenzoate gave 85% active-sites indicating a homogenous population of molecules; therefore, the propositus is a homozygote. Four different plasminogen activators: a) streptokinase, b) urokinase c) the plasmin-derived light (B) chain-streptokinase complex, and d) tissue plasminogen activator (with soluble fibrin/CNBr-fibrinogen fragments) generated little plasmin from the variant plasminogen (4.5 to 45 nM), 5% or less than that generated from normal plasminogen. At 45 nM plasminogen, the molar ratio of plasminogen:activator was 3.0 for streptokinase, 3.9 for urokinase, 7.1 for the light (B) chain-streptokinase complex, and 155 for tissue plasminogen activator. In the equimolar variant plasminogen.streptokinase complex, the active-site was slowly developed, to a maximum of 85% in 40 min; in the normal complex, 100% active-sites were developed in 15 min. The variant plasminogen forms two equimolar complexes with streptokinase (I and II), with different mobilities in PAGE, in about equal amounts.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Abnormal plasminogen Maywood I. 180 22

Plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) have been studied with spectrophotometric methods in extracts of human, bovine, ovine and rat kidneys of both sexes. In all species studied, renal PAA (cortex or medulla) was higher in females than in males. The PAA was also higher in the medulla than in the cortex in all species and both sexes. The PAA was due to both types of plasminogen activator; tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA). In the human kidney (cortex or medulla) the measurement of t-PA antigen showed that t-PA is higher in females than in males; t-PA is also higher in the medulla than in the cortex in both sexes. The PAI showed the opposite pattern in all species studied; it was lower in females than in males. It was also lower in the medulla than in the cortex. PAI-1 was identified in the human kidney. Sex-related differences in renal PAA or PAI almost disappeared after bilateral orchidectomy in rats. PI showed no sex or regional differences in the species studied. Sex-related differences in renal PAA and PAI in man and various animal species might be of physiological or pathophysiological importance.
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PMID:Sex-related differences in plasminogen activator activity and plasminogen activator inhibition of human and animal kidneys: effect of orchidectomy or ovariectomy. 180 59

The question whether single-chain urokinase-type plasminogen activator (Sc-uPA) possesses an enzymatic activity has been a subject of intense investigation for a number of years but still remains unresolved. Recent studies from several laboratories suggest that Sc-uPA or its plasmin-resistant mutants obtained by site-directed mutagenesis possess significant, albeit low, amidolytic and plasminogen activator activities, ranging from 0.1% to 1% of that observed for two-chain urokinase (Tc-uPA). In an effort to characterize these putative intrinsic activities, Sc-uPA was repeatedly treated with dansyl-Glu-Gly-Arg chloromethyl ketone (dansyl-EGRck) or diisopropyl fluorophosphate (DFP) (0.1-0.25 mM added thrice over a period of 24 h at 0 degrees C). This treatment exhaustively inactivated the Tc-uPA contaminant but did not affect Sc-uPA, as evidenced by the lack of significant incorporation of radiolabeled inhibitor in Sc-uPA and full activation of the inhibitor-treated Sc-uPA by plasmin. Assayed in the presence of excess DFP or dansyl-EGRck to ensure trapping of any Tc-uPA generated in the assay mixture, Sc-uPA (84 micrograms/mL, 10,500 latent units/mL) did not elicit any detectable cleavage of the chromogenic substrate S-2444 (detection limit 0.1 unit of Tc-uPA/mL). However, if the Tc-uPA inhibitors were removed prior to assay, a trace amount of amidolytic activity invariably reappeared in the Sc-uPA preparation. Incorporation experiments with [3H]DFP suggested that the appearance of this amidolytic activity was due to formation of Tc-uPA. Plasminogen activator assay of DFP- and dansyl-EGRck-treated Sc-uPA (0.45-2.25 microM), performed in the presence of these inhibitors and Trasylol (10 microM) to ensure entrapment of any Tc-uPA or plasmin generated in the reaction mixture, showed no significant cleavage of 125I-labeled plasminogen (detection limit 0.1 nM). However, if dansyl-EGRck and DFP were removed from the inhibitor-treated Sc-uPA and the assay was performed in the presence of Trasylol alone, there was significant cleavage of 125I-plasminogen due to contamination by Tc-uPA. Fibrin, a positive effector of plasminogen activation by Tc-uPA or Sc-uPA preparations in the absence of DFP and dansyl-EGRck, did not promote cleavage of plasminogen or S-2444 by Sc-uPA in the presence of the Tc-uPA inhibitors.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Single-chain urokinase-type plasminogen activator does not possess measurable intrinsic amidolytic or plasminogen activator activities. 182 71

Plasminogen activation on the cell surface is regulated by a variety of modulators which balance surface-bound plasminogen activators (PAs) and plasminogen activator inhibitors (PAIs). In this study, we developed as assay system to assess modulation of cell-associated plasminogen activation. Plasmin generation by endogenous plasminogen activators was measured with a combination of exogenously added plasminogen and a chromogenic substrate, S-2251, in the presence of living cells. A cell surface PA activity was quantitated by adopting a rate of plasmin generation. We used HT-1080, a human fibrosarcoma cell line, as representative of cells which have both PAs and PAIs on their cell surface. A basal level of cell surface PA activity was specifically reduced by anti-urokinase-type PA IgG and enhanced by anti-PAI-1 IgG, suggesting that the basal level is determined by a balance between uPA and PAI-1 on the cell surface. We examined effects of dexamethasone and thrombin on cell surface PA activity in the assay system. Dexamethasone appeared to suppress the cell surface PA activity by enhancing de novo synthesis of PAI-1, whereas thrombin suppressed it by inactivating single-chain urokinase-type plasminogen activators. These results indicate that our assay system can be adapted for the screening of various types of PA modulators.
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PMID:An assay system for the modulators of plasminogen activation on the cell surface. 189 67

This study evaluates the contribution of two types of plasminogen activators (PAs; tissue-type PA (tPA) versus urokinase-type PA (uPA) toward the invasiveness of human melanoma cells in a novel in vitro assay. We identified two human melanoma cell lines, MelJuso and MeWo, expressing uPA or tPA as shown at mRNA, protein, and enzyme activity level. MelJuso cells produced uPA as well as plasminogen activator inhibitor-1 (PAI-1). The latter was, however, not sufficient to neutralize the cell-associated or secreted uPA activity. MeWo cells secreted tPA, but the enzyme was not found to be cell-associated. PAI-1 production by these cells was not detectable. Plasminogen activation and fibrinolytic capacity of both cell lines were reduced by anticatalytic monoclonal antibodies specific for the respective type of PA or by aprotinin. In a novel in vitro invasion assay, antibodies to PA as well as aprotinin decreased the invasiveness of both cell lines into a fibrin gel, Matrigel, or intact extracellular matrix. Our results confirm the importance of uPA-catalyzed plasminogen activation in tumor cell invasiveness. Furthermore, we provide evidence that tPA, beyond its key role in thrombolysis, can also be involved in in vitro invasion of human melanoma cells.
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PMID:Urokinase-type and tissue-type plasminogen activators are essential for in vitro invasion of human melanoma cells. 189 72

Plasminogen activators are serine proteinases which transform the serum zymogen, plasminogen, into plasmin, a broad-spectrum protease with fibrinolytic effect. Two main plasminogen activators have been described in humans: urokinase (UK; molecular weight, 55,000) and tissue-type plasminogen activator (tPA; molecular weight, 74,000). Thirteen subjects were studied who had alopecia areata (AA), nine in the active phase and four in remission. There were alterations in the perivascular and peribulbar fibrinolytic activity in the nine subjects in the active phase of disease, suggesting a possible role of plasminogen activators in AA. A modified Todd's autohistographic method was used to evaluate cutaneous fibrinolytic activity (which depended on the activity of plasminogen activators) in the 13 AA subjects and five volunteer controls. Cutaneous fibrinolytic activity was reduced in perivascular areas, but increased in peribulbar areas, in the nine subjects in the active phase of disease. Tests with monoclonal antibodies directed against the catalytic sites of tPA and UK showed that the perivascular fibrinolytic activity was tPA dependent, and the peribulbar fibrinolytic activity was UK dependent.
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PMID:The role of plasminogen activators in alopecia areata. 189 52

Plasminogen activator activity was investigated in extracts of 42 surgically removed gastric carcinomas. The mean levels of total plasminogen activator (total-PA) and urokinase-type plasminogen activator (u-PA) activities in the gastric carcinomas were significantly higher than those in the background normal tissues (p less than 0.001). On electrophoresis, gastric cancers were found to contain u-PA as the predominant PA, this being confirmed using zymography by direct inhibition with anti-urokinase antibody. Assessment of the relationship between PA activity and biological behavior of gastric cancer revealed total-PA and u-PA levels to be significantly higher in differentiated than in undifferentiated tumors (p less than 0.001), and in aneuploid than in diploid ones (p less than 0.01). Immunohistochemical staining showed that the proportion of u-PA-positive cancer cells in the carcinoma tissues also correlated with activity as measured by the azocaseinolytic method. These findings suggest that the study of PA contents in gastric cancer, combined with a nuclear DNA ploidy and immunohistochemical analysis, might be useful for understanding the biological characteristics of the tumor.
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PMID:Plasminogen activators in human gastric cancers: correlation with DNA ploidy and immunohistochemical staining. 190 1

Plasminogen activators (PA), particularly the lower Mr urokinase (u-PA) type, have been associated with tumor cell invasion and metastasis. We have examined the expression of PA by two human prostate cancer cell lines (PC-3 and DU-145) using functional and immunologic techniques. The culture media and cell extracts of the more aggressive PC-3 cell line contained more than two-fold greater PA activity than the relatively indolent DU-145 cell line. Zymographic studies identified the PA expressed as u-PA. PC-3 cells expressed an additional lower molecular weight form of u-PA not noted in DU-145 cells. Heterogeneity in u-PA expression was shown by the fibrin lysis assay, immunohistochemistry, and dual parameter flow cytometry indicating the presence of phenotypically divergent cell populations. Increased u-PA expression may identify those tumor cells that possess aggressive biological potential.
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PMID:Heterogeneity in plasminogen activator (PA) levels in human prostate cancer cell lines: increased PA activity correlates with biologically aggressive behavior. 190 92


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