EFFECT OF THE NEPHRITOGENIC AUTOANTIBODY OF HEYMANNS NEPHRITIS ON PLASMINOGEN-BINDING TO GP330 AND ACTIVATION BY UROKINASE

Authors
Citation
Jj. Kanalas, EFFECT OF THE NEPHRITOGENIC AUTOANTIBODY OF HEYMANNS NEPHRITIS ON PLASMINOGEN-BINDING TO GP330 AND ACTIVATION BY UROKINASE, Biochimica et biophysica acta, 1225(1), 1993, pp. 101-106
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biophysics,Biology
ISSN journal
0006-3002
Volume
1225
Issue
1
Year of publication
1993
Pages
101 - 106
Database
ISI
SICI code
0006-3002(1993)1225:1<101:EOTNAO>2.0.ZU;2-1
Abstract
Previous results have shown that the autoantibody eluted from the glom eruli of rats with active Heymann nephritis contain a population of an tibodies not only to the putative autoantigen of the disease, gp330, b ut also to plasminogen. Since gp330 has been shown to serve as a recep tor for plasminogen, we have analyzed the effects of autoantibody on p lasminogen-binding to gp330 and activation of plasminogen to plasmin b y urokinase. Autoantibody does not inhibit the binding of plasminogen to gp330. The binding of autoantibody to plasminogen was shown to be v ery specific for the compact conformation of glu-plasminogen. The chan ge in the conformation of plasminogen when its lysine-binding sites ar e occupied or after conversion to plasmin results in a significant dec rease in autoantibody-binding. The most significant effect of autoanti body on this system is the inhibition of plasminogen activation to pla smin by urokinase. The binding of autoantibody to plasminogen acts as a competitive inhibitor of the reaction by apparently blocking access of urokinase to plasminogen's activation site. These results indicate that autoantibody obtained from the immune deposits in the glomeruli o f rats with active Heymann nephritis does not inhibit the binding of p lasminogen to gp330 but does significantly alter the urokinase catalyz ed activation of plasminogen to plasmin.