Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urokinase (UK) and streptokinase (SK) transform plasminogen into plasmin by rupture of a ARG-VAL bond and the liberation of a peptide with a molecular weight of 6000 to 8000. Urokinase is a physiological activator with a direct action. By contrast, streptokinase is an enzyme of bacterial origin and two hypotheses may be advanced to explain its mechanism of action: the formation of a SK-plasminogen complex capable of activatiing new molecules of plasminogen or the formation of a SK-plasminogen complex within which plasminogen is transformed to plasmin.
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PMID:[Enzymatic fibrinolytic agents]. 3 Nov 12

In two of four non-enzymatically treated gamma-globulin preparations C Immunoglobulin Schura, Immunoglobulin SRK), the distribution of IgG subclasses was found to be close to that of normal human serum. In two other preparations (sulphonated and beta-propiolactone-treated) IgG3 was not detectable by means of appropriate antiserum. The IgG residual portion of plasmin-treated gamma-globulin was enriched in IgG2, while IgG3 was absent. In affinity chromatography on protein A Sepharose, IgG3 in the unbound and IgG1, IgG2 and IgG4 in the bound fractions were found in Immunoglobulins Schura and SRK. In the sulphonated preparation no IgG was found in the unbound fraction, while IgG1, IgG2 and IgG4 were eluted from the bound fraction. In beta-propiolactone-treated gamma-globulin IgG1, IgG2 and IgG4 were present in both fractions. The testing of reactivity of IgG subclasses with Staphylococcus protein A can supply important information about the state of the Fc part in immunoglobulin preparations.
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PMID:IgG subclasses in human gamma-globulin preparations for intravenous use and their reactivity with staphylococcus protein A. 615 36

The presence of a proteolytic activity in sera from pregnant humans and rodents capable of degrading insulin-like growth factor binding protein-3 (IGFBP-3) has been known for some time. However, the identity of this activity has remained elusive. We have attempted to purify the IGFBP-3 protease activity from pregnant human serum (PHS) using the degradation of 125I-IGFBP-3 as a marker. Following ammonium sulfate precipitation of PHS and further enrichment of active fractions by ion-exchange, protein-A Sepharose, and size-exclusion chromatography, a protease of approximately 70-90 kDa was isolated and subjected to N-terminal analysis. The N-terminal sequence was consistent with plasminogen, a known fibrinolytic enzyme. To further characterize the IGFBP-3 protease activities in both PHS and nonpregnant human serum (NHS), aliquots of serum were first enriched by polyethylene glycol-precipitation and subjected to size-exclusion chromatography. The size-separated fractions were then incubated with 125I-IGFBP-3, and proteolytic activity was measured. PHS contained two separate proteases (>150 kDa and 70-90 kDa), whereas NHS contained only one (70-90 kDa) that had a inhibitor profile similar to plasmin. However, inhibitors of plasmin had no effect on the activity of the >150-kDa protease. Plasminogen activators (PAs) greatly increased the activity of the 70- to 90-kDa protease, but had little effect on the >150-kDa protease activity. Addition of PAs greatly increased the ability of NHS to proteolyze IGFBP-3. In contrast, the ability of plasminogen-depleted plasma to degrade 125I-IGFBP-3 was not affected by the addition of PAs. Both urokinase and tissue-type PA had the ability to proteolyze IGFBP-3 and were, in contrast to the >150-kDa protease activity, inhibited by the specific PA inhibitor D-PHE-PRO-ARG chloromethyl ketone. The present data suggest that sera has the ability to proteolyze IGFBP-3, and that this ability, as demonstrated by NHS, can be regulated by protease inhibitors and PAs. In addition, PHS does indeed contain an unique IGFBP-3 protease activity that is not present in NHS, and its identity is unknown at this time.
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PMID:Human pregnancy serum contains at least two distinct proteolytic activities with the ability to degrade insulin-like growth factor binding protein-3. 927 81

Angiopoietin-1 (Ang1) is a strong inducer of endothelial cell sprouting, which is a first step in both angiogenesis and neovascularization. We examined the mechanisms underlying Ang1-induced cell sprouting using porcine pulmonary artery endothelial cells. Ang1 induced the nondirectional and directional migration of endothelial cells mediated through the Tie2 but not the Tie1 receptor. Ang1 induced tyrosine phosphorylation of p125(FAK), and this phosphorylation was dependent on phosphatidylinositol (PI) 3'-kinase activity. Ang1 induced the secretion of plasmin and matrix metalloproteinase-2 (MMP-2), which is inhibited by PI 3'-kinase inhibitors. Ang1 also induced the secretion of small amounts of proMMP-3 and proMMP-9 but not proMMP-1. Ang1 suppressed the secretion of tissue inhibitor of metalloproteinase-2 (TIMP-2), but not of TIMP-1. Addition of alpha(2)-antiplasmin, a combination of TIMP-1 and TIMP-2, or PI 3'-kinase inhibitors inhibited Ang1-induced sprouting activity. Therefore, Ang1-induced sprouting activity in endothelial cells may be accomplished by cytoskeletal changes and secretion of proteinases and may be largely mediated through intracellular PI 3'-kinase activation.
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PMID:Angiopoietin-1 induces endothelial cell sprouting through the activation of focal adhesion kinase and plasmin secretion. 1080 67

The mechanism of proinflammatory activation of human monocytes by plasmin is unknown. Here we demonstrate that in human primary monocytes, plasmin stimulates mitogen-activated protein kinase (MAPK) signaling via phosphorylation of MAPK kinase 3/6 (MKK3/6) and p38 MAPK that triggers subsequent DNA binding of transcription factor activator protein-1 (AP-1). The AP-1 complex contained phosphorylated c-Jun and ATF2, and its DNA binding activity was blocked by the p38 MAPK inhibitor SB203580. In addition, plasmin elicits Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling, as detected by phosphorylation of JAK1 tyrosine kinase and STAT1 and STAT3 proteins. Plasmin-induced DNA binding of STAT1 and STAT3 was blocked by SB203580 and AG490, inhibitors of p38 MAPK and JAK, respectively, but not by U0126, an inhibitor of MKK1/2. DNA binding of NF-kappaB remained unaffected by any of these inhibitors. The plasmin-induced signaling led to expression of monocyte chemoattractant protein-1 (MCP-1) and CD40, which required activation of both p38 MAPK and JAK/STAT signaling pathways. Additionally, signaling through both p38 MAPK and JAK is involved in the plasmin-mediated monocyte migration, whereas the formylmethionylleucylphenylalanine-induced chemotaxis remained unaffected. Taken together, our data demonstrate a novel function of the serine protease plasmin in a proinflammatory signaling network.
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PMID:The serine protease plasmin triggers expression of MCP-1 and CD40 in human primary monocytes via activation of p38 MAPK and janus kinase (JAK)/STAT signaling pathways. 1209 96

Endogenously produced dicarbonyls, such as methylglyoxal (MG), are involved in advanced glycation end-product formation and thus linked to the pathophysiology of diabetic chronic complications. While the search for synthetic new antiglycation agents continues, little attention has been paid to putative antiglycation agents in natural compounds. Given the link between glycation and oxidation, in this work, we study the effects of methylglyoxal on two model systems; plasminogen and antithrombin III (AT III), then we set out to unravel a possible antiglycation effect for extracts of the flavonoid-rich common herbal species Achyrocline satureoides (AS) and Ilex paraguariensis (IP). Using SAR-PRO-ARG-pNA as a specific thrombin substrate, we show that incubation of plasma with MG decreases heparin activation of AT III by up to a 70%, in a dose-dependent manner. A parallel dose-dependent decrease in plasminogen activity reaching more than 50% was shown using D-BUT-CHT-lys-pNA as a plasmin-specific substrate. Extracts of AS and IP display a dose dependent inhibition of the action of the dicarbonyl, already significant at a 1/100 dilution of the herbal infusions. The inhibition was comparable to that obtained by using millimolar concentrations of known AGE inhibitors such as aminoguanidine and carnosine as well as micromolar concentrations of the antioxidant ascorbic acid. We believe our system of whole plasma glycation over 16 h with micromolar concentrations of MG, coupled with the measurement of activities of plasminogen and AT III by specific substrates provides a straightforward, practical method for monitoring the action of putative antiglycation agents. If predictably milder glycated forms of AT III and plasminogen were to be secreted in vivo, the loss of activities shown here could act synergistically to generate hyperthrombicity.
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PMID:The botanical extracts of Achyrocline satureoides and Ilex paraguariensis prevent methylglyoxal-induced inhibition of plasminogen and antithrombin III. 1242 87

Objectives We undertook the present work to device a simple method to study the effects of inhibitors on functional impairment of proteins by the action of glycating agents. Design and methods For that purpose, we first tested the feasibility and optimized the conditions to employ glycation of human plasma coupled with AT III and plasminogen activity measurement, using coagulation test kits available in most clinical laboratories. Results Using D-BUT-CHT-lys-pNA as a plasmin-specific substrate, we show that incubation of plasma with fructose, glyceraldehyde or MG but not glucose decreases plasminogen activity reaching more than 40% in 16 h. A parallel dose-dependent decrease in heparin activation of AT III by up to a 50% was demonstrated using SAR-PRO-ARG-pNA as a specific thrombin substrate. We studied the effects of aminoguanidine, carnosine, quercetin aglycone, alpha tocopherol and ascorbic acid. Conclusion The methods afforded good discrimination between the known different reactivities of glycating sugars as well as the action of known antiglycation agents. They provide a practical system for monitoring the action of putative antiglycation agents.
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PMID:A practical method to study functional impairment of proteins by glycation and effects of inhibitors using current coagulation/fibrinolysis reagent kits. 1263 66

A number of RGD-type integrins rely on a synergistic site in addition to the canonical RGD site for ligand binding and signaling, although it is still unclear whether these two recognition sites function independently, synergistically, or competitively. Experimental evidence has suggested that fibrinogen binding to the RGD-type integrin alphaIIbbeta3 occurs exclusively through the synergistic gamma(400-411) sequence, thus questioning the functional role of the RGD recognition site. Here we have investigated the respective role of the fibrinogen gamma(400-411) sequence and the RGD motif in the molecular events leading to ligand-induced alphaIIbbeta3-dependent Chinese hamster ovary (CHO) cell or platelet spreading, by using intact fibrinogen and well characterized plasmin-generated fibrinogen fragments containing either the RGD motif (fragment C) or the gamma(400-411) sequence (fragment D), and CHO cells expressing resting wild type (alphaIIbbeta3wt), constitutively active (alphaIIbbeta3T562N), or non-functional (alphaIIbbeta3D119Y) receptors. Our data provide evidence that the gamma(400-411) site by itself is able to initiate alphaIIbbeta3 clustering and recruitment of intracellular proteins to early focal complexes, mediating cell attachment, FAK phosphorylation, and Rac1 activation, while the RGD motif subsequently acts as a molecular switch on the beta3 subunit to trigger cell spreading. More importantly, we show that the premier functional role of the RGD site is not to reinforce cell attachment but, rather, to imprint a conformational change on the beta3 subunit leading to maximal RhoA activation and actin cytoskeleton organization in CHO cells as well as in platelets. Finally, alphaIIbbeta3-dependent RhoA stimulation and cell spreading, but not cell attachment, are Src-dependent and phosphoinositide 3-kinase-independent and are inhibited by the Src antagonist PP2.
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PMID:A new functional role of the fibrinogen RGD motif as the molecular switch that selectively triggers integrin alphaIIbbeta3-dependent RhoA activation during cell spreading. 1595 23

The serine-protease urokinase (uPA) and its specific membrane receptor uPAR controls matrix degradation through the conversion of plasminogen into plasmin and play a crucial role in a number of biological processes including local fibrinolysis, inflammation, angiogenesis, matrix remodelling during wound healing, tumor invasion and metastasis. Most of the cellular responses modulated by the uPA/uPAR system, including migration, cellular adhesion, differentiation, proliferation and apoptosis require transmembrane signaling, which is mediated by direct contacts of uPAR with a variety of extracellular proteins and membrane receptors, such as integrins, EGF receptor, high molecular weight kininogen, caveolin and the G-protein-coupled receptor FPRL1. As a result of these interactions, uPAR activates intracellular signalling molecules such as tyrosine- and serine-protein kinases, Src, focal adhesion kinase (FAK), Rac, extracellular-signal-regulated kinase (ERK)/mitogen- activated protein kinase (MAPK) and JAK/STAT, being part of a large "signalosome" interacting with several molecules on both the outside and inside of the cell. This review is focused on the biochemistry of the pathways affected by uPAR and its partners.
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PMID:The urokinase receptor as an entertainer of signal transduction. 1927 72

We characterized the interactions between plasminogen and neurons and investigated the associated effects on extracellular matrix proteolysis, cell morphology, adhesion, signaling and survival. Upon binding of plasminogen to neurons, the plasmin formed by constitutively expressed tissue plasminogen activator (tPA) degrades extracellular matrix proteins, leading to retraction of the neuron monolayer that detaches from the matrix. This sequence of events required both interaction of plasminogen with carboxy-terminal lysine residues and the proteolytic activity of plasmin. Surprisingly, 24h after plasminogen addition, plasmin-detached neurons survived and remained associated in clusters maintaining focal adhesion kinase phosphorylation contrasting with other adherent cell types fully dissociated by plasmin. However, long-term incubation (72 h) with plasminogen was associated with an increased rate of apoptosis, suggesting that prolonged exposure to plasmin may cause neurotoxicity. Regulation of neuronal organization and survival by plasminogen may be of pathophysiological relevance, as plasminogen is expressed in the brain and/or extravasate during vascular accidents or inflammatory processes.
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PMID:Role of plasminogen activation in neuronal organization and survival. 1968 75


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