Involvement of finger domain and kringle 2 domain of tissue-type plasminogen activator in fibrin binding and stimulation of activity by fibrin.

Verheijen, J.H.; Caspers, Martien P. M.; Chang, Glenn T.G.; Munk, G.A.W. de; Pouwels, Peter H.; Enger-Valk, B.E.

doi:10.1002/j.1460-2075.1986.tb04678.x

Cited by 173 publications

(108 citation statements)

References 26 publications

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“…the finger domain binds fibrin (14) and annexin II (37,38), and the kringle domains, in particular the second kringle domain, also bind fibrin (13,14). Our results show that the interaction of tPA with PDGF-CC is mediated through specific interaction of the kringle-2 domain.…”

Section: Discussionmentioning

confidence: 73%

“…It is best known for its role in vascular fibrinolysis where it converts the zymogen plasminogen into plasmin, which in turn degrades the fibrin network in blood clots. The observation that tPA binds to fibrin via its finger and kringle-2 domains (13,14), thus facilitating a localized generation of plasmin, has focused much attention on the use of tPA as a thrombolytic agent. In fact, tPA is currently used to treat acute myocardial infarction and is also approved for treatment of acute ischemic stroke (15).…”

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confidence: 99%

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Structural Requirements for Activation of Latent Platelet-derived Growth Factor CC by Tissue Plasminogen Activator

Fredriksson

Ehnman

Fieber

et al. 2005

Journal of Biological Chemistry

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Platelet-derived growth factor C (PDGF-C) is one of four members in the PDGF family of growth factors, which are known mitogens and survival factors for cells of mesenchymal origin. PDGF-C has a unique twodomain structure consisting of an N-terminal CUB and a conserved C-terminal growth factor domain that are separated by a hinge region. PDGF-C is secreted as a latent dimeric factor (PDGF-CC), which undergoes extracellular removal of the CUB domains to become a PDGF receptor ␣ agonist. Recently, the multidomain serine protease tissue plasminogen activator (tPA), a thrombolytic agent used for treatment of acute ischemic stroke, was shown to cleave and activate PDGF-CC. In this study we determine the molecular mechanism of tPA-mediated activation of PDGF-CC. Using various PDGF-CC and tPA mutants, we were able to demonstrate that both the CUB and the growth factor domains of PDGF-C, as well as the kringle-2 domain of tPA, are required for the interaction and cleavage to occur. We also show that Arg 231 in PDGF-C is essential for tPAmediated proteolysis and that the released "free" CUB domain of PDGF-C can act as a competitive inhibitor of the cleavage reaction. Furthermore, we studied how the PDGF-C/tPA axis is regulated in primary fibroblasts and found that PDGF-C expression is downregulated by hypoxia but induced by transforming growth factor (TGF)-␤ 1 treatment. Elucidating the regulation and the mechanism of tPA-mediated activation of PDGF-CC will advance our knowledge of the physiological function of PDGF-CC and tPA and may provide new therapeutic opportunities for thrombolytic and cardiovascular therapies.

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Section: Discussionmentioning

confidence: 73%

mentioning

confidence: 99%

Structural Requirements for Activation of Latent Platelet-derived Growth Factor CC by Tissue Plasminogen Activator

Fredriksson

Ehnman

Fieber

et al. 2005

Journal of Biological Chemistry

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“…Using purified components, investigators have demonstrated that t-PA initially binds to fibrin through the finger domain which is not a lysine binding site (3). Further binding may occur through the kringle 2 domain as fibrin undergoes digestion by plasmin with exposure of C-terminal lysine sites on fibrin (27)(28)(29).…”

Section: Discussionmentioning

confidence: 99%

Inhibitory effects of lysine analogues on t-PA induced whole blood clot lysis

Krishnamurti

Vukelja

Alving

1994

Thrombosis Research

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“…There are 5 distinct structural domains in tPA, comprising Finger-Growth factor-Kringle 1-Kringle 2-protease (F-G-K1-K2-P). Many potential binding sites are available on tPA for cells and fibrin, but the most important sites for fibrinolysis appear to be in the F and K2 domains, [14][15][16] and refined mutagenetic analysis indicates that K2 is less involved in fibrin binding than expected. 17 However, studies performed to date do not take into consideration the specific roles of tPA domains in fibrin of variable structure as well as their distinct function in the rearranging fibrin architecture in the course of lysis.…”

Section: Introductionmentioning

confidence: 99%

The interplay between tissue plasminogen activator domains and fibrin structures in the regulation of fibrinolysis: kinetic and microscopic studies

Longstaff

Thelwell

Williams

et al. 2011

Blood

118

137

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Regulation of tissue-type plasminogen activator (tPA) depends on fibrin binding and fibrin structure. tPA structure/ function relationships were investigated in fibrin formed by high or low thrombin concentrations to produce a fine mesh and small pores, or thick fibers and coarse structure, respectively. Kinetics studies were performed to investigate plasminogen activation and fibrinolysis in the 2 types of fibrin, using wild-type tPA (F-G-K1-K2-P, F and K2 binding), K1K1-tPA (F-G-K1-K1-P, F binding), and delF-tPA (G-K1-K2-P, K2 binding). There was a trend of enzyme potency of tPA > K1K1-tPA > delF-tPA, highlighting the importance of the finger domain in regulating activity, but the differences were less apparent in fine fibrin. Fine fibrin was a better surface for plasminogen activation but more resistant to lysis. Scanning electron and confocal microscopy using orange fluorescent fibrin with green fluorescent protein-labeled tPA variants showed that tPA was strongly associated with agglomerates in coarse but not in fine fibrin. In later lytic stages, delF-tPA-green fluorescent protein diffused more rapidly through fibrin in contrast to full-length tPA, highlighting the importance of finger domainagglomerate interactions. Thus, the regulation of fibrinolysis depends on the starting nature of fibrin fibers and complex dynamic interaction between tPA and fibrin structures that vary over time. (Blood. 2011;117(2):661-668) IntroductionFibrin may be viewed as a substrate according to 2 distinct definitions of the word: (1) a surface or layer supporting biologic activity and (2) a substance acted on by an enzyme. The mechanism of tissue-type plasminogen activator (tPA) stimulation by fibrin is by "colocalization" of tPA and plasminogen on fibrin, which acts as a substrate (definition 1) or template; and the plasmin generated in this way is the enzyme that digests fibrin substrate (definition 2). Fibrinolysis encompasses both processes, which are distinct but overlapping. The role of fibrin structure in regulating the whole process of fibrinolysis is not completely understood, and there is disagreement over published results. For example, fibrin fiber diameter can be manipulated by thrombin, such that higher thrombin concentrations produce a fine network of thin fibers, whereas fibrin polymerization at lower thrombin concentration results in more lateral aggregation and produces clots composed of thicker fibers, as reviewed. 1 It has been observed from gross changes in turbidity of fibrin clots undergoing lysis 2,3 that clots made of thicker fibers appear to lyse more rapidly than clots made from fine fibers. However, this simple relationship has been questioned because clots made of thicker fibers are more turbid and lysis may appear to be faster when followed optically if turbidity is not normalized to correct for different starting values. 1 Furthermore, it has been noted from more detailed microscopic studies that thinner fibers are more susceptible to lysis than thick fibers, yet this relationship is not reflecte...

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Involvement of finger domain and kringle 2 domain of tissue-type plasminogen activator in fibrin binding and stimulation of activity by fibrin.

Cited by 173 publications

References 26 publications

Structural Requirements for Activation of Latent Platelet-derived Growth Factor CC by Tissue Plasminogen Activator

Structural Requirements for Activation of Latent Platelet-derived Growth Factor CC by Tissue Plasminogen Activator

Inhibitory effects of lysine analogues on t-PA induced whole blood clot lysis

The interplay between tissue plasminogen activator domains and fibrin structures in the regulation of fibrinolysis: kinetic and microscopic studies

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