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.
Besta
Felicitas
F
Medizinische Klinik, Klinikum rechts der Isar und Deutsches Herzzentrum, Lazarettstrasse 36, 80636 Münich, Germany.
Massberg
Steffen
S
Brand
Korbinian
K
Müller
Elke
E
Page
Sharon
S
Grüner
Sabine
S
Lorenz
Michael
M
Sadoul
Karin
K
Kolanus
Waldemar
W
Lengyel
Ernst
E
Gawaz
Meinrad
M
D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D006224:Cricetinae; D003593:Cytoplasm / Q000378:metabolism; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D009154:Mutation; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D015534:Trans-Activators / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014471:Umbilical Veins / Q000166:cytology
C403295:ITGB3BP protein, human; D008164:Luminescent Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; C524898:PLAUR protein, human; D011506:Proteins; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011994:Recombinant Proteins; D015534:Trans-Activators; D049452:Green Fluorescent Proteins