scholarly journals Cell surface-mediated activation of progelatinase A: demonstration of the involvement of the C-terminal domain of progelatinase A in cell surface binding and activation of progelatinase A by primary fibroblasts

1994 ◽  
Vol 304 (1) ◽  
pp. 263-269 ◽  
Author(s):  
R V Ward ◽  
S J Atkinson ◽  
J J Reynolds ◽  
G Murphy

We report that the isolated C-terminal domain of progelatinase A is inhibitory to the activation of this proenzyme by primary skin fibroblast plasma membranes but is unable to inhibit organomercurial-induced self-cleavage and activation. Ligand binding studies demonstrate that fibroblasts stimulated with concanavalin A to activate progelatinase A have a significantly enhanced level of cell surface-associated progelatinase A. Tissue inhibitor of metalloproteinases-2 (TIMP-2), an effective inhibitor of membrane-mediated progelatinase A activation, is able to abolish the enhanced level of cell surface-associated progelatinase A that occurs following stimulation. TIMP-1, a poor inhibitor of membrane activation, is unable to inhibit the cell surface binding of progelatinase A. The enhancement in the binding of 125I-progelatinase A to fibroblasts following concanavalin A stimulation can be blocked by the inclusion of excess C-terminal gelatinase A but not by a truncated form of gelatinase A lacking the C-terminal domain. Scatchard analysis of the binding of 125I-progelatinase A to concanavalin A-stimulated fibroblasts has identified 950,000 gelatinase binding sites per cell with a Kd of 1.3 x 10(-8) M. Analysis of non-stimulated fibroblasts has identified 500,000 sites per cell with a Kd of 2.6 x 10(-8) M. We propose that membrane-mediated activation of progelatinase A involves binding of the proenzyme through its C-terminal domain to the cell surface and that TIMP-2 can inhibit activation by interaction with progelatinase A through the C-terminal domain, thus preventing binding of the proenzyme.

FEBS Letters ◽  
1996 ◽  
Vol 385 (3) ◽  
pp. 238-240 ◽  
Author(s):  
Hiroshi Sato ◽  
Takahisa Takino ◽  
Takeshi Kinoshita ◽  
Kazushi Imai ◽  
Yasunori Okada ◽  
...  

1984 ◽  
Vol 220 (3) ◽  
pp. 665-675 ◽  
Author(s):  
T Wileman ◽  
R L Boshans ◽  
P Schlesinger ◽  
P Stahl

Binding studies with cells that had been permeabilized with saponin indicate that alveolar macrophages have an intracellular pool of mannose-specific binding sites which is about 4-fold greater than the cell surface pool. Monensin, a carboxylic ionophore which mediates proton movement across membranes, has no effect on binding of ligand to macrophages but blocks receptor-mediated uptake of 125I-labelled beta-glucuronidase. Inhibition of uptake was concentration- and time-dependent. Internalization of receptor-bound ligand, after warming to 37 degrees C, was unaffected by monensin. Moreover, internalization of ligand in the presence of monensin resulted in an intracellular accumulation of receptor-ligand complexes. The monensin effect was not dependent on the presence of ligand, since incubation of macrophages with monensin at 37 degrees C without ligand resulted in a substantial decrease in cell-surface binding activity. However, total binding activity, measured in the presence of saponin, was much less affected by monensin treatment. Removal of monensin followed by a brief incubation at pH 6.0 and 37 degrees C, restored both cell-surface binding and uptake activity. Fractionation experiments indicate that ligands enter a low-density (endosomal) fraction within the first few minutes of uptake, and within 20 min transfer to the lysosomal fraction has occurred. Monensin blocks the transfer from endosomal to lysosomal fraction. Lysosomal pH, as measured by the fluorescein-dextran method, was increased by monensin in the same concentration range that blocked ligand uptake. The results indicate that monensin blockade of receptor-mediated endocytosis of mannose-terminated ligands by macrophages is due to entrapment of receptor-ligand complexes and probably receptors in the pre-lysosomal compartment. The inhibition is linked with an increase in the pH of acid intracellular vesicles.


Biochemistry ◽  
1999 ◽  
Vol 38 (44) ◽  
pp. 14524-14533 ◽  
Author(s):  
Jim W. Burgess ◽  
Philippe G. Frank ◽  
Vivian Franklin ◽  
Ping Liang ◽  
Dan C. McManus ◽  
...  

1993 ◽  
Vol 268 (7) ◽  
pp. 5279-5284
Author(s):  
B.S. Weeks ◽  
K. Desai ◽  
P.M. Loewenstein ◽  
M.E. Klotman ◽  
P.E. Klotman ◽  
...  

1991 ◽  
Vol 266 (28) ◽  
pp. 18655-18659 ◽  
Author(s):  
P.F. Blackmore ◽  
J. Neulen ◽  
F. Lattanzio ◽  
S.J. Beebe

2004 ◽  
Vol 287 (1) ◽  
pp. L210-L216 ◽  
Author(s):  
Dirk Haufe ◽  
Thomas Luther ◽  
Matthias Kotzsch ◽  
Lilla Knels ◽  
Thea Koch

Intrapulmonary application of perfluorocarbons (PFC) in acute lung injury is associated with anti-inflammatory effects. A direct impact on leukocytic function may be involved. To further elucidate PFC effects on cellular activation, we compared in an in vitro model the response of concanavalin A (ConA)-stimulated lymphocytes and monocytes exposed to perfluorohexane. We hypothesized that perfluorohexane attenuates the action of the lectin ConA by altering stimulant-receptor interaction on the cell surface. Mononuclear blood cells were stimulated by incubation with ConA in the presence of different amounts of perfluorohexane. The response of lymphocytes and monocytes was determined by means of IL-2 secretion and tissue factor (TF) expression, respectively. The influence of perfluorohexane on cell-surface binding of fluorescence-labeled ConA was studied using flow cytofluorometry and fluorescence microscopy. Perfluorohexane itself did not induce a cellular activation but significantly inhibited both monocytic TF expression and, to a far greater extent, IL-2 secretion of ConA-stimulated mononuclear blood cells. The effect of perfluorohexane was due neither to an alteration of cell viability nor to a binding of the stimulant. The amount of cell surface-bound ConA was not altered by perfluorohexane, and the overall pattern of ConA receptor rearrangement did not differ between controls and treated cells. In the present study, we provide further evidence for an anti-inflammatory effect of PFC that might be beneficial in states of pulmonary hyperinflammation. A PFC-induced alteration of stimulant-receptor interaction on the surface membrane does not seem to be the cause of attenuated cell activation.


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