Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular matrix (ECM), prepared from chick embryo fibroblasts, contains fibronectin as the major structural protein along with collagen and other polypeptides as less abundant protein components. When Rous sarcoma virus-transformed chick embryo fibroblasts are cultured on the ECM in the presence of the tumor promoter tetradecanoyl phorbol acetate, the transformed cells lose their characteristic rounded morphology and align on and within the ECM fibrillar network. This restrictive aspect of ECM is only temporary, however, and with time (24-72 h) the transformed cells progressively degrade the ECM fibers and resume their rounded appearance. The matrix degradation can be monitored by employing biosynthetically radiolabeled ECM. The addition of purified chicken plasminogen to the Rous sarcoma virus-transformed chick embryo fibroblast cultures enhances the rate and extent of ECM degradation, due to the elevated levels in the transformed cultures of plasminogen activator. Plasminogen-dependent and -independent degradation of ECM has been characterized with regard to sensitivity to various natural and synthetic protease inhibitors and to the requirement of cell/ECM contact. Plasminogen-dependent degradation of ECM occurs rapidly when ECM and cells are in contact or separated, whereas plasminogen-independent degradation is greatly reduced when ECM and cells are separated, which suggests that cell surface-associated proteolytic enzymes are involved. A possible role in ECM degradation has been indicated for cysteine proteases, metallo enzymes, and plasminogen activator, the latter as both a zymogen activator and a direct catalytic mediator.
 ...
PMID:The extracellular matrix of normal chick embryo fibroblasts: its effect on transformed chick fibroblasts and its proteolytic degradation by the transformants. 299 35

The cell extracts and conditioned medium from cultured bovine capillary endothelial (BCE) cells were examined to determine the types of plasminogen activator (PA) present in each of these two fractions. The fractions were first analyzed by fibrin autography after sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The cell extracts contained two species of PA of Mr 48,000 and 28,000. Multiple forms of PA were detected in the conditioned medium: variable amounts of the Mr 48,000 and 28,000 forms and a broad band of activity with Mr in the range of 67,000-93,000. The major fraction of the Mr 48,000 form was in the cell extract. Treatment of the cells with 12-0-tetradecanoyl phorbol-13-acetate or with a preparation containing angiogenic activity resulted in a proportionate increase in the levels of all forms. The Mr 48,000 form was demonstrated to be a urokinase-like PA, since it was immunoprecipitated with antibodies to urokinase. When conditioned medium or cell extracts from biosynthetically labelled BCE cells were incubated with antiserum to urokinase, the Mr 48,000 form was immunoprecipitated only from the cell extract. The Mr 67,000-93,000 forms were demonstrated to be tissue-type PAs, since they were immunoprecipitated with antibodies to tissue PA. When the same conditioned medium or cell extracts were incubated with antiserum to tissue-type PA, the Mr 67,000-93,000 forms were immunoprecipitated only from the conditioned medium. Therefore, BCE cells are able to produce both tissue-type PA, which is primarily secreted, and urokinase-type PA, which remains primarily cell associated.
 ...
PMID:Urokinase-type and tissue-type plasminogen activators have different distributions in cultured bovine capillary endothelial cells. 308 99

The purpose of this study was to determine whether human polymorphonuclear neutrophils (PMN), which share a common cell lineage with macrophages, could produce factors such as IL 1. Other properties which these two cell types share are their phagocytic nature and the common receptor and antigens on their cell surfaces. IL 1, in many of its physical, biochemical, and functional characteristics, is found to resemble endogenous pyrogen (EP). PMN have been cited as a possible cell source of EP, but there have also been reports in which the capacity of PMN to produce EP has been questioned. This study shows that normal human PMN can be stimulated by particulate agents such as zymosan and soluble agents such as phorbol myristic acetate to produce a factor(s) which induces proliferation of mouse thymocytes, i.e., PMN IL 1. This PMN IL 1 was released from PMN in a dose- and time-dependent fashion. PMN IL 1 was nondialyzable, was heat-labile, and was inactivated at pH below 5 and above 8. PMN IL 1 stimulated the proliferation of normal human synovial fibroblasts and caused release of a neutral protease (plasminogen activator) from synovial cells. The synovial and thymocyte-proliferating capacity of PMN IL 1 was not affected by the protease inhibitor aprotinin or by soybean trypsin inhibitor. Gel filtration studies estimate the m.w. of PMN IL 1 to be approximately 13,000 to 17,000.
 ...
PMID:Interleukin 1 production by human polymorphonuclear neutrophils. 308 39

Phorbol ester (12-O-tetradecanoyl-phorbol 13-acetate) stimulates the secretion of tissue-type plasminogen activator by the melanoma cell line, Bowes. This effect is associated with increased levels of mRNAs for both tissue-type plasminogen activator and a 48 kDa-protein. Labelling of melanoma cells with L-[35S]methionine allowed to identify an intracellular protein which, by 3 criteria, was identical with the in vitro translation product of the 48kDa-protein mRNA: a Mr of 48,000 on electrophoresis in the presence of sodium dodecyl sulphate; inducibility by phorbol ester and failure of reducing agents to affect electrophoretic mobility. As detectable by L-[35S]methionine labelling, the protein was mainly localized in the cytosol. In vitro phosphorylation reactions, carried out on subcellular fractions revealed a membrane-associated protein which also had the three characteristics of the aforementioned 48 kDa-protein. Phosphorylation did not require Ca2+-ions. Addition of phorbol ester to the reaction mixtures increased the phosphorylation. Reconstitution experiments between membrane and cytosol fractions of phorbol ester-treated and untreated cells showed that the 48kDa protein occurs in a cytosolic, unphosphorylated and a membrane-bound, phosphorylated form and that the former is converted to the latter by a phorbol ester activated, membrane-associated protein kinase.
 ...
PMID:Phorbol ester stimulates the synthesis and phosphorylation of a 48 kDa-intracellular protein in plasminogen activator secreting melanoma cells. 308 56

We report the production, purification, characterization, and partial amino acid sequence of a plasminogen inhibitor (PA-I). The starting material is culture fluid from phorbol myristate 13-acetate-treated U-937 cells and the isolation steps consist of preparative isoelectric focusing followed by affinity chromatography on Cibacron Blue-Sepharose. PA-I migrates as a closely spaced doublet of 47-kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and forms covalent complexes with urokinase and two-chain tissue-type plasminogen activator, displaying second order rate constants of 0.9 X 10(6) M-1 s-1 and 0.2 X 10(6) M-1 s-1, respectively. Upon treatment with 1 M NH4OH, the covalent complexes were hydrolyzed, yielding a 35-kDa inhibitor fragment. A partial amino acid sequence of PA-I showed that it belongs to the antithrombin III family of inhibitors. PA-I is immunologically related to a PA-inhibitor from human placenta. mRNA from phorbol myristate 13-acetate-treated U-937 cells directed, in a rabbit reticulocyte derived cell-free system, the biosynthesis of only one 47-kDa protein that could be immunoprecipitated with anti-PA-I IgG, indicating that the two molecular forms of PA-I are the products of post-translational processing.
 ...
PMID:Purification and characterization of a plasminogen activator inhibitor from the histiocytic lymphoma cell line U-937. 309 45

A rapid and high-yield procedure for the purification of single polypeptide tissue-type plasminogen activator (t-PA) from porcine heart tissue has been developed. Delipidated heart tissue was extracted with 0.45 M potassium acetate. The extract was fractionated with ammonium sulfate and purified by a combination of affinity chromatography on heparin-Sepharose CL-6B and gel filtration on Toyopearl HW-55S. The final product had a specific activity of 220,000 IU/mg protein and gave a single protein band (apparent molecular weight; 67,000) in SDS-polyacrylamide gels in the presence or absence of a reducing agent. The increase in specific activity was 3,200-fold, most of which was achieved in the step of heparin-Sepharose chromatography. The yield calculated from the active ammonium sulfate precipitate was about 90% and 500 micrograms or more of the purified enzyme was obtained from 1 kg wet tissue. This procedure may also be useful for the large-scale production of highly purified t-PA from other tissues or tissue culture cells.
 ...
PMID:Rapid and high-yield purification of porcine heart tissue-type plasminogen activator by heparin-sepharose choromatography. 309 93

Macrophage products induce production of proteases that contribute to cartilage degradation in various joint diseases. In these studies we stimulated rabbit chondrocytes with various cytokines in vitro in order to determine which were responsible for changes in the release of prostaglandin, plasminogen activator, and a metalloproteinase. The metalloproteinase assayed in these studies is a latent enzyme whose activity can rapidly be measured with fluorogenic casein. Conditioned media from stimulated human peripheral blood mononuclear cells; purified human monocyte IL 1, pI 7,6, and 5; and recombinant human IL 1, beta or alpha forms, all changed the secretory pattern of rabbit articular chondrocytes in a similar manner: production and secretion of a latent metalloproteinase(s) and prostaglandin E were stimulated in a concentration-dependent fashion, whereas the activity of plasminogen activator was strongly reduced. Antibodies against human monocyte IL 1 blocked the active principle in various mononuclear cell-conditioned media, suggesting that uncharacterized factors present in these supernatants do not affect the metalloproteinase response. When added to confluent chondrocytes, phorbol myristate acetate, concanavalin A, IL 2, lipopolysaccharide, indomethacin, and prostaglandin E2, which interfere with lymphocyte proliferation assays for IL 1, failed to influence chondrocyte metalloproteinase secretion. Recombinant human IFN-alpha or IFN-gamma in the presence or absence of IL 1 had no effect on rabbit chondrocytes, whereas recombinant human tumor necrosis factor decreased plasminogen activator but had no effect on prostaglandin or metalloproteinase production. These results support the concept that IL 1 specifically induces chondrocytes to produce metalloproteinases, and hence may play an important role in destructive joint diseases.
 ...
PMID:Human monocyte or recombinant interleukin 1's are specific for the secretion of a metalloproteinase from chondrocytes. 309 47

Analysis of conditioned medium from three sublines of the B16 melanoma [F1 (parental), BL6 (invasive), F10 (metastatic)] by SDS-PAGE and zymography revealed the presence of plasminogen activator activity at 60,000 daltons. The relative activity was F10 greater than F1 greater than or equal to BL6. Treatment of the cells with the tumor promoter, phorbol myristate acetate (PMA) led to increased secretion of PA by F10 cells and a lesser increase in secretion by F1 cells and BL6 cells. In addition, a second plasminogen activator activity at 45,000 daltons was detected in conditioned medium from PMA treated F10 cells. Conditioned medium from F10 and F1 cells was also shown to contain a 33,000 dalton plasminogen activator binding protein. Upon PMA treatment the concentration of the binding protein increased in medium from F10 cells but not in similarly treated F1 cells. The binding protein, very likely a plasminogen activator inhibitor, was nearly undetectable in conditioned medium from control and PMA-treated BL6 cells. Therefore, the three sublines, which differ in in vivo phenotypic characteristics, also differ in their in vitro regulation of proteinase and proteinase inhibitor synthesis.
 ...
PMID:Differences between the F10, BL6 and F1 sublines of the B16 melanoma in the enhancement of plasminogen activator and plasminogen activator inhibitor secretion by phorbol myristate acetate. 310 64

Mouse resident peritoneal macrophages synthesize two plasminogen activator-specific inhibitors (PAI) that are functionally and antigenically related, but differ in their apparent Mr and oligosaccharide content. Most of the Mr 40,000 inhibitor can be recovered from the cell lysate, whereas the Mr 55,000 glycosylated PAI is preferentially secreted. The murine macrophage PAI are functionally similar and immunologically related to PAI synthesized and secreted by human monocytes-macrophages, and to a PAI from human placenta (PAI-2). PAI production by murine mononuclear phagocytes can be modulated both in vivo and in vitro. Bone marrow-derived macrophages do not produce detectable PAI, whereas inflammatory macrophages obtained from thioglycollate-induced peritoneal exudates produce only low levels of PAI. In cultures of resident peritoneal macrophages, phorbol myristate acetate and cholera toxin increase the synthesis of the Mr 55,000 secreted PAI, whereas dexamethasone decreases the synthesis of both PAI; the production of PAI is also enhanced in the presence of macrophage colony-stimulating factor (CSF-1). The overall proteolytic activity of mononuclear phagocytes thus depends in part on the controlled synthesis and secretion of PAI. The balance between the production of plasminogen activators and of their inhibitors could be critical in determining the level of plasminogen-dependent extracellular proteolysis associated with different phases of the inflammatory response.
 ...
PMID:Plasminogen activator-specific inhibitors in mouse macrophages: in vivo and in vitro modulation of their synthesis and secretion. 311 28

Phospholipases (PL) A-2 and C stimulated the outputs of prostaglandin (PG) F-2 alpha, PGE-2 and 6-keto-PGF-1 alpha from the Day-7 and Day-15 guinea-pig uterus superfused in vitro. PLC had a more pronounced effect than PLA-2, particularly on the output of PGE-2. The ratios of the outputs of PGF-2 alpha and PGE-2 were similar after stimulation by A23187 and PLA-2, but this ratio was lower after stimulation by PLC. It appears that the stimulation of endometrial PGF-2 alpha synthesis by Ca2+ is via activation of PLA-2 rather than via activation of PLC, although the PLC used was of bacterial origin (which uses phosphatidylcholine as substrate) rather than of mammalian origin (which uses phosphatidylcholine as substrate). Forskolin (which increased endometrial and myometrial cyclic AMP levels) and phorbol 12-myristate-13-acetate had no effect on uterine PG output, indicating that cyclic AMP and protein kinase C are not involved in the stimulation of endometrial PGF-2 alpha synthesis in the guinea-pig. Uterine PG output was not stimulated by 54 mM-KCl, which shows that the pulsatile nature of endometrial PGF-2 alpha synthesis and release is not due to an intermittent, synchronous depolarization of the endometrial cells.
 ...
PMID:Effects of various factors on prostaglandin synthesis by the guinea-pig uterus. 311 14


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>