Matches in Nanopublications for { <http://www.tkuhn.ch/bel2nanopub/RACG6etm2fLk4aHpq3d6Il4VNBH64Ljvlj2eeSuai3AY4#_7> ?p ?o ?g. }
Showing items 1 to 2 of
2
with 100 items per page.
- _7 wasQuotedFrom 11841347 provenance.
- _7 value "The amino terminal fragment of urokinase, which binds to uPAR with high affinity but lacks proteolytic activity, also suppressed tube formation in fibrin matrix, possibly due to competition with the endogenous uPA for the binding to uPAR [167]. Taken together, these findings have demonstrated that the uPAR localized cell surface proteolysis plays an important role in tubular angiogenesis. Targeting the uPA-uPAR system may be useful to affect these early events in angiogenesis. This viewpoint is in accordance with the finding that angiogenesis occurring in certain tumors in vivo can be reduced by administration of a catalytically inactive uPA, which retains receptor binding and thus competes for binding of native uPA [168]. The expression of urokinase and its receptor have been shown immunohistochemically in endothelial cells involved in formation of tubules in fibrin matrices [167]. The fact that a few cells in the unstimulated monolayer are positive for uPAR may reflect the existence of a subpopulation of cells that are more able to invade the fibrin matrix if adequate stimuli, which induce uPA expression are provided [169]. Beside a function in controling of spatially focalized degradation of the basement membrane, uPA bound to uPAR influences angiogenesis also by the activation of intracellular signal systems in endothelial cells. Thus, it activates MAP-kinases and the phosphorylation of focal adhesion proteins [170]. Analysis by immunoblotting demonstrated tyrosine phosphorylation of focal adhesion kinase (FAK), the focal adhesion-associated proteins paxillin and p130cas, and mitogen-activated protein kinase (MAPK) following the occupancy of the uPAR by uPA." provenance.