Analysis of mitochondrial antigens reveals inner membrane succinate dehydrogenase flavoprotein subunit as autoantigen to antibodies in anti-M7 sera.
The role of mitochondrial proteins as antigens to antibodies of anti-M7 sera was analysed by flavin fluorescence, one- and two-dimensional Western blots and blue native gel electrophoresis. Flavin fluorescence of succinate dehydrogenase (SucDH, complex II of the respiratory chain) of rat liver inner mitochondrial membranes correlated with the immunoreactivity of a representative anti-M7 myocarditis serum. Antigens of isolated bovine heart mitochondria reacting with antibodies of myocarditis serum on two-dimensional Western blots were identified by MALDI-TOF and NanoESI mass spectrometry as myosin heavy chain beta and as dihydrolipoamide dehydrogenase of the mitochondrial 2-oxoacid dehydrogenase complexes. The SucDH-flavoprotein was not resolved as a discrete protein spot on two-dimensional polyacrylamide gels. However, separation of the rat liver inner mitochondrial membrane complexes by blue native gel electrophoresis followed by Western blotting, and Western blots of purified Escherichia coli SucDH complex revealed that anti-M7 sera contained antibodies directed against the SucDH-flavoprotein subunit.
Cicek
G
G
Institut für Biochemie und Molecularbiologie, Institut für Organische Chemie und Biochemie, Abteilung Innere Medizin, Universitätsklinikum, Universität Freiburg, Freiburg, Germany.
Schiltz
E
E
Hess
D
D
Staiger
J
J
Brandsch
R
R
D000818:Animals; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D015153:Blotting, Western; D002417:Cattle; D042963:Electron Transport Complex II; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology; D005415:Flavins / Q000737:chemistry; D005420:Flavoproteins / Q000737:chemistry; D005453:Fluorescence; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000276:immunology*; D009097:Multienzyme Complexes / Q000737:chemistry / Q000276:immunology*; D009205:Myocarditis / Q000276:immunology*; D010088:Oxidoreductases / Q000737:chemistry / Q000276:immunology*; D021122:Protein Subunits; D051381:Rats; D013385:Succinate Dehydrogenase / Q000737:chemistry / Q000276:immunology*
D001323:Autoantibodies; D001324:Autoantigens; D005415:Flavins; D005420:Flavoproteins; D024101:Mitochondrial Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; D010088:Oxidoreductases; D042963:Electron Transport Complex II; D013385:Succinate Dehydrogenase