Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sympathetic neurons release both urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA). A number of inhibitors of serine proteases have been tested to determine their effects on neurite outgrowth from rat sympathetic neurons. Some inhibitors increase neurite outgrowth while others have little or no effect on outgrowth. Inhibition of plasminogen activator (PA) activity but not other serine protease activity correlates with the increase in neurite outgrowth (uPA, r = 0.89; tPA, r = 0.86; plasmin, r = 0.015; thrombin, r = 0.025). Antibodies that inhibit uPA activity increase neurite outgrowth, while antibodies that bind to uPA but do not inhibit activity do not alter outgrowth. Time-lapse videomicroscopy of neurite outgrowth indicates that about 85% of the neurites increase their rate of outgrowth following exposure to inhibitors of PA. Routinely, 1-2 min after exposure of a growth cone to an inhibitor, there is an increase in lamellipodial activity at the leading edge of the growth cone and a decrease in lamellipodial activity on the sides and base of the growth cone. The increase in the rate of outgrowth combined with the decrease in lamellipodial activity on the sides of the growth cones results in neurites being very long and straight in the presence of inhibitors (persistence time P = 3.7 and 15.3 hr for controls and in the presence of inhibitors of PA, respectively). PAs released from sympathetic neurons and PC12 cells interact with 3 different binding sites on the cell surface: (1) an inhibitor of serine proteases (including uPA and tPA) is bound to the surface via a heparinase-sensitive site; (2) a uPA-selective binding site is present in patches on the bottom surface of PC12 cells; and (3) a tPA-selective binding site with high affinity (KD = 23 +/- 10 nM) and high capacity (340,000 +/- 130,000 sites/neuron) for 125I-tPA is homogeneously distributed over the entire surface. Data in the present study are consistent with PA being involved in neurite outgrowth and open the possibility of other PA-dependent functions occurring when tPA and/or uPA interacts with cell surface binding sites.
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PMID:Neuronal plasminogen activators: cell surface binding sites and involvement in neurite outgrowth. 251 75

The serine protease, prostate-specific antigen (PSA), its protein substrates, semenogelin (Sg) I and II, and protein C inhibitor (PCI) have been described as components of human seminal plasma. PCI was found to inhibit the PSA-catalyzed degradation of insoluble coagula Sg I + II by forming a PSA-PCI complex. Digestion of seminal coagula with PSA released PCI and PSA-PCI complex from the coagula into a soluble phase, suggesting the presence of active PCI binding to the coagula. To investigate the molecular interaction of Sg with PSA and PCI, we purified Sg II from seminal coagula as a soluble form and found that Sg II is glycosylated with heterogeneous carbohydrate moieties. Sg II bound to the solid-phase complex of diisopropylfluorophosphate (iPr2FP) and PSA with an apparent dissociation constant (kd) of 41 nM and to PCI with a Kd of 28 nM. The binding of Sg II to iPr2P-PSA was not affected by PCI and that of Sg II to PCI was not affected by iPr2P-PSA, suggesting that Sg II forms a ternary complex with PSA and PCI. The bindings of Sg II to both iPr2P-PSA and PCI were influenced by pH, ionic strength, heparin, dextran sulfate, and divalent cations, particularly by Zn2+. Treatment of Sg II with heparinase, heparitinase, N-glycanase, or with O-glycanase following sialidase did not affect the binding of Sg II to iPr2P-PSA and PCI. These findings suggested that PCI bound to Sg in seminal vesicles regulates the PSA-catalyzed degradation of Sg in seminal plasma, and that the binding of PCI and PSA to Sg is modulated by several factors such as pH, ionic strength, divalent cations, and heparin-like substances in seminal plasma.
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PMID:Characterization of semenogelin II and its molecular interaction with prostate-specific antigen and protein C inhibitor. 866 56

Granzyme B (GzmB), a serine protease of cytotoxic T lymphocytes and natural killer (NK) cells, induces apoptosis by caspase activation after crossing the plasma membrane of target cells. The mechanism of this translocation during killer cell attack, however, is not understood. Killer cells release GzmB and the membrane-disturbing perforin at the contact site after target recognition. Receptor-mediated import of glycosylated GzmB and release from endosomes were suggested, but the role of the cation-independent mannose 6-phosphate receptor was recently refuted. Using recombinant nonglycosylated GzmB, we observed binding of GzmB to cellular membranes in a cell type-dependent manner. The basis and functional impact of surface binding were clarified. GzmB binding was correlated with the surface density of heparan sulfate chains, was eliminated on treatment of target cells with heparinase III or sodium chlorate, and was completely blocked by an excess of catalytically inactive GzmB or GzmK. Although heparan sulfate-bound GzmB was taken up rapidly into intracellular lysosomal compartments, neither of the treatments had an inhibitory influence on apoptosis induced by externally added streptolysin O and GzmB or by natural killer cells. We conclude that membrane receptors for GzmB on target cells are not crucial for killer cell-mediated apoptosis.
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PMID:Membrane receptors are not required to deliver granzyme B during killer cell attack. 1552 17

Atrial natriuretic peptide (ANP) is a cardiac hormone essential for normal blood pressure and cardiac function. Corin is a transmembrane serine protease that activates ANP. Recently, we identified proprotein convertase subtilisin/kexin-6 (PCSK6), also called PACE4, as the long-sought corin activator. Both corin and PCSK6 are expressed in cardiomyocytes, but corin activation occurs only on the cell surface. It remains unknown if cell membrane association is needed for PCSK6 to activate corin. Here we expressed corin deletion mutants in HEK293 cells to analyze the domain structures required for PCSK6-mediated activation. Our results show that soluble corin lacking the transmembrane domain was activated by PCSK6 in the conditioned medium but not intracellularly. Recombinant PCSK6 also activated the soluble corin under cell-free conditions. Moreover, PCSK6-mediated corin activation was not enhanced by cell membrane fractions. These results indicate that cell membrane association is unnecessary for PCSK6 to activate corin. Experiments with monensin that blocks PCSK6 secretion and immunostaining indicated that the soluble corin and PCSK6 were secreted via different intracellular pathways, which may explain the lack of corin activation inside the cell. We also found that the protein domains in the corin pro-peptide region were dispensable for PCSK6-mediated activation and that addition of heparan sulfate and chondroitin sulfate or treatment with heparinase or chondroitinase did not alter corin activation by PCSK6 in HEK293 cells. Together, our results provide important insights into the molecular and cellular mechanisms underlying PCSK6-mediated corin activation that is critical for cardiovascular homeostasis.
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PMID:Functional analysis of corin protein domains required for PCSK6-mediated activation. 2918 Mar 4