Role of beta(3)-endonexin in the regulation of NF-kappaB-dependent expression of urokinase-type plasminogen activator receptor.
Endothelial migration on extracellular matrix is regulated by integrins and proteolysis. Previous studies showed that beta(3)-integrins regulate expression of the urokinase-type plasminogen activator receptor (uPAR) through outside-in signalling involving the cytoplasmic domain. Here we show that overexpression of the integrin-binding protein beta(3)-endonexin decreased uPAR promoter (-398 base-pair fragment) activity that ... is constitutively active in endothelial cells. Mutation of the NF-kappaB promoter binding site (-45 bp) impaired the ability of beta(3)-endonexin to downregulate uPAR promoter activity. Immunoprecipitation studies showed that beta(3)-endonexin interacts directly with the p50/p65 transactivation complex and thereby inhibits binding of kappaB oligonucleotides to the p50/p65 complex. Moreover, binding of beta(3)-endonexin to p50 was inhibited in the presence of kappaB but not mutated kappaB oligonucleotides, suggesting a sterical competition between beta(3)-endonexin and kappaB DNA for the p50/p65 complex. We therefore propose that beta(3)-endonexin acts as regulator of uPAR expression in beta(3)-integrin-mediated endothelial cell migration through direct interaction with p50/p65. Since NF-kappaB regulates the expression of matrix degrading enzymes, the present results define a role of beta(3)-endonexin in regulating beta(3)-integrin-mediated adhesion and pericellular proteolysis.
Mesh Terms:
Animals, Binding Sites, CHO Cells, Cell Line, Cell Nucleus, Cricetinae, Cytoplasm, Down-Regulation, Endothelium, Vascular, Gene Expression Regulation, Green Fluorescent Proteins, Humans, Luminescent Proteins, Mutation, NF-kappa B, Nuclear Proteins, Promoter Regions, Genetic, Proteins, Receptors, Cell Surface, Receptors, Urokinase Plasminogen Activator, Recombinant Proteins, Sequence Deletion, Trans-Activators, Transcription, Genetic, Transcriptional Activation, Umbilical Veins
Animals, Binding Sites, CHO Cells, Cell Line, Cell Nucleus, Cricetinae, Cytoplasm, Down-Regulation, Endothelium, Vascular, Gene Expression Regulation, Green Fluorescent Proteins, Humans, Luminescent Proteins, Mutation, NF-kappa B, Nuclear Proteins, Promoter Regions, Genetic, Proteins, Receptors, Cell Surface, Receptors, Urokinase Plasminogen Activator, Recombinant Proteins, Sequence Deletion, Trans-Activators, Transcription, Genetic, Transcriptional Activation, Umbilical Veins
J. Cell. Sci.
Date: Oct. 15, 2002
PubMed ID: 12244126
View in: Pubmed Google Scholar
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