Stopped‐flow fluorescence kinetic studies of Glu‐plasminogen Conformational changes triggered by AH‐site ligand binding

Christensen, Ulla; Mølgaard, Lone

doi:10.1016/0014-5793(91)80117-l

Cited by 16 publications

(23 citation statements)

References 14 publications

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“…Cooperativity between binding sites was previously noted in plasminogen, the parent molecule of plasmin which contains similar binding sites ( Fig. 7 in [33], [35]); Takada et al also suggested mutual interactions between LBS in plasminogen [36]. A second phenomenon of positive co-operativity induced by oleic acid relates to the interaction of plasmin with the substrate S-2251 (Fig.…”

Section: Discussionmentioning

confidence: 64%

Stimulation of plasmin activity by oleic acid

Higazi

Finci-Yeheskel

Samara

et al. 1992

Biochemical Journal

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The amidolytic activity of plasmin with the chromogenic substrate H-D-valyl-L-leucyl-L-lysine p-nitroanilide (S-2251) is stimulated by oleic acid in a dose-dependent and saturable fashion. The activity of plasmin on S-2251 in the presence of oleic acid followed a sigmoidal kinetic pattern, with an almost 4-fold stimulation of activity at 60 microM-oleic acid. Half-maximal stimulation occurred at an oleic acid level of 19.5 microM. The amino acid analogue 6-aminohexanoic acid (AHA), which is known to bind to lysine-binding sites in plasmin, suppressed the stimulatory effect of oleic acid in a concentration-dependent manner; at 0.3 mM-AHA, about 70% of the oleic acid-dependent enhancement of plasmin activity was abolished. The l/v versus 1/[S] plot for plasmin changed in the presence of oleic acid from a linear to a non-linear curve, suggesting positive co-operativity. 14C-labelled oleic acid bound to plasmin, and the bound ligand was displaced by an excess of unlabelled oleic acid. Oleic acid also produced a marked (40-fold) stimulation of the plasminogen-dependent cleavage of S-2251 by urokinase. A half-maximal effect on plasminogen activation was obtained at 40 microM-oleic acid. The present findings suggest that the ability of oleic acid to stimulate plasmin activity and to enhance the conversion of plasminogen to plasmin depends on the interaction of oleic acid with specific lysine-binding sites in plasmin.

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Section: Discussionmentioning

confidence: 64%

Stimulation of plasmin activity by oleic acid

Higazi

Finci-Yeheskel

Samara

et al. 1992

Biochemical Journal

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“…1 [13]) also is valid for each of the glycoforms individually. All other schemes previously considered [12, 13]cannot account for these data. Consequently, equation 2 of Scheme.…”

Section: Resultsmentioning

confidence: 99%

Glycosylation at Asn‐289 facilitates the ligand‐induced conformational changes of human Glu‐plasminogen

Mølgaard¹,

Ponting²,

Christensen³

1997

FEBS Letters

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“…Small changes in the total fluorescence of glu-plasminogen (typically 10%) in the presence of lysine analogues or proteins are representative of lysine-dependent conformational changes to the zymogen (Christensen and Molgaard, 1991;Andronicos et al, 2000). Similarly, the change in total fluorescence of FITC-glu-plasminogen in the presence of MDA-MB-231 cells increased to a maximum of approximately 10% in a time-dependent manner ( Figure 1B).…”

Section: Stability and Conformation Of Cell Bound Plasminogenmentioning

confidence: 99%

The topology of plasminogen binding and activation on the surface of human breast cancer cells

Andronicos

Ranson

2001

Br J Cancer

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SummaryThe urokinase-dependent activation of plasminogen by breast cancer cells plays an important role in metastasis. We have previously shown that the metastatic breast cancer cell line MDA-MB-231 over-expresses urokinase and binds and efficiently activates plasminogen at the cell surface compared to non-metastatic cells. The aim of this study was to further characterise plasminogen binding and determine the topology of cell surface-bound plasminogen in terms of its potential for activation. The lysine-dependent binding of plasminogen at 4˚C to MDA-MB-231 cells was stable and resulted in an activation-susceptible conformation of plasminogen. Topologically, a fraction of bound plasminogen was co-localised with urokinase on the surfaces of MDA-MB-231 cells where it could be activated to plasmin. At 37˚C plasmin was rapidly lost from the cell surface. Apart from actin, other candidate plasminogen receptors were either not expressed or did not co-localise with plasminogen at the cell surface. Thus, based on co-localisation with urokinase, plasminogen binding is partitioned into two functional pools on the surface of MDA-MB-231 cells. In conclusion, these results shed further light on the functional organisation of the plasminogen activation cascade on the surface of a metastatic cancer cell.

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Stopped‐flow fluorescence kinetic studies of Glu‐plasminogen Conformational changes triggered by AH‐site ligand binding

Cited by 16 publications

References 14 publications

Stimulation of plasmin activity by oleic acid

Stimulation of plasmin activity by oleic acid

Glycosylation at Asn‐289 facilitates the ligand‐induced conformational changes of human Glu‐plasminogen

The topology of plasminogen binding and activation on the surface of human breast cancer cells

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