Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor-alpha (TNF alpha) is a central mediator in the pathogenesis of sepsis. It also interferes with the hemostatic system and exerts and a net procoagulant effect. Since TNF alpha may contribute to thrombotic complications in sepsis patients, we determined markers of thrombin activation, parameters of the fibrinolytic system (D-dimer, tissue plasminogen activator antigen (tPA) urinary type plasminogen activator antigen (uPA), plasminogen activator inhibitor antigen (PAI-1) and von Willebrand factor antigen (vWF) in 30 patients with sepsis or septic shock. All patients were treated with standard therapy, but 14 patients were treated additionally with an anti-TNF alpha monoclonal antibody (MAK 195F); 16 patients served as historical controls. No significant effect of the antibody on the parameters of the hemostatic system could be determined. Our data speak against a modulation of coagulation or the fibrinolytic system by the monoclonal anti-TNF alpha antibody MAK 195F in this cohort of sepsis patients.
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PMID:Hemostatic parameters in sepsis patients treated with anti-TNF alpha-monoclonal antibodies. 890 37

The release of [3H]arachidonic acid was studied in the 1321N1 astrocytoma cell line upon stimulation with thrombin. The effect of thrombin was antagonized by hirudin only when both compounds were added simultaneously, which suggests activation of thrombin receptor. Evidence that the cytosolic phospholipase A2 (cPLA2) takes part in thrombin-induced arachidonate release was provided by the finding that thrombin induced retardation of the mobility of cPLA2 in SDS/polyacrylamide gels, which is a feature of the activation of cPLA2 by mitogen-activated protein (MAP) kinases. Thrombin induced activation of two members of the MAP kinase family whose consensus primary sequence appears in cPLA2, namely p42-MAP kinase and c-Jun kinase. However, the activation of c-Jun kinase preceded the phosphorylation of cPLA2 more clearly than the activation of p42-MAK kinase did. Both cPLA2 and c-Jun kinase activation were not affected by PD-98059, a specific inhibitor of MAP kinase kinases, which indeed completely blocked p42-MAP kinase shift. Heat shock, a well-known activator of c-Jun kinase, also phosphorylated cPLA2 but not p42-MAP kinase. These data indicate the existence in astrocytoma cells of a signalling pathway triggered by thrombin receptor stimulation that activates a kinase cascade acting on the Pro-Leu-Ser-Pro consensus primary sequence, activates cPLA2, and associates the release of arachidonate with nuclear signalling pathways.
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PMID:Thrombin produces phosphorylation of cytosolic phospholipase A2 by a mitogen-activated protein kinase kinase-independent mechanism in the human astrocytoma cell line 1321N1. 935 63

Biotin-dependent enzymes contain a biotinyl-lysine residue in a conserved sequence motif, MKM, located in a surface hairpin turn in one of the two beta-sheets that make up the domain. A sub-gene encoding the 82-residue C-terminal biotinyl domain from the biotin carboxy carrier protein of acetyl-CoA carboxylase from Escherichia coli as a fusion protein with glutathione S-transferase was created and over-expressed in E. coli. The biotinyl domain was readily released by cleavage with thrombin. Five mutant domains were created in which the conserved MKM motif was systematically replaced: by MAK and KAM, in which the target lysine is moved one place; by KKM and MKK, in which a second potential site for biotinylation is introduced; and by DKA, the motif found in the correspondingly conserved site of lipoylation in the structurally related lipoyl domains of 2-oxo acid dehydrogenase multienzyme complexes. No biotinylation of the MAK or KAM mutants was observed in vivo or by purified biotinyl protein ligase in vitro; in the KKM and MKK mutants, only one lysine residue, presumed to be that in its native position in the hairpin turn, was found to be biotinylated in vivo and in vitro. The DKA mutant was not biotinylated in vivo, but was partly lipoylated and octanoylated. It was also a poor substrate for lipoylation in vitro catalysed by the E. coli lipoyl protein ligase encoded by the lplA gene. The flanking sequence in the MKM motif is important, but not crucial, and appears to have been conserved in part to be compatible with the subsequent carboxylation reactions of biotin-dependent enzymes. The DKA motif, displayed in the hairpin loop, is sufficient to address lipoylation in E. coli but probably by a pathway different from that mediated by the lplA-dependent ligase. The recognition of the structurally homologous lipoyl and biotinyl domains by the appropriate ligase evidently has a major structural component to it, notably the positioning of the target lysine residue in the exposed hairpin loop, but there appear to be additional recognition sites elsewhere on the domains.
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PMID:Selectivity of post-translational modification in biotinylated proteins: the carboxy carrier protein of the acetyl-CoA carboxylase of Escherichia coli. 944 86

We examined the mechanism of thrombin on proliferation of synovial fibroblasts obtained from rheumatoid arthritis (RA). Thrombin concentration-dependently induced proliferation of synovial fibroblasts. Proliferation in response to thrombin (10 U/ml) was completely blocked by hirudin. TP367 and TP508, peptides corresponding to 2 noncatalytic regions of thrombin, failed to induce cell proliferation. Thrombin did not induce the production of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) in synovial fibroblasts. Expression of proteinase-activated receptor (PAR)-1 and PAR-3 mRNAs was observed in synovial fibroblasts. Thrombin and PAR-1 agonist peptide (AP), but not PAR-3 AP, induced intracellular calcium mobilization. PAR-1 AP induced cell proliferation whereas PAR-3 AP and PAR-4 AP had no effect on proliferation. Pertussis toxin (PTX), a Gialpha protein inhibitor; wortmannin, a PI (phosphatidylinositol) 3-kinase inhibitor; and PD98059, a specific MEK [mitogen-activated protein (MAK) kinase kinase] inhibitor, inhibited the thrombin-induced cell proliferation. Furthermore, the proliferation of synovial fibroblasts was suppressed by U-73122, a PLC (phospholipase C) inhibitor; 2-APB, an antagonist of InsP3 (inositol 1,4,5-triphosphate) receptor; and GF-109203X, a PKC (protein kinase C) inhibitor. These results suggest that thrombin induces the proliferation of RA synovial fibroblasts through the activation of PAR-1, leading to the PTX-sensitive G proteins - PI3 kinase pathway and PTX-insensitive G proteins - PLC (InsP3 receptor) Ca(2+)-PKC branch.
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PMID:Thrombin-stimulated proliferation of cultured human synovial fibroblasts through proteolytic activation of proteinase-activated receptor-1. 1878 3