Epitope mapping of mitochondrial adenine nucleotide translocase-1 in idiopathic dilated cardiomyopathy.
Mitochondrial adenine nucleotide translocase (ANT) is a specific target for the autoantibody response in idiopathic dilated cardiomyopathy (IDCM). We have undertaken an epitope analysis of ANT in IDCM by immunoblot with recombinant GST-ANT fusion proteins and with cellulose-bound decapeptides of human ANT1. Forty-five patients with IDCM, 17 patients with ischemic left ventricle dysfunction (LVD) and 20 controls were analyzed for circulating antibodies against ANT (AAb-ANT). Sixteen of the 45 (36%) IDCM patients showed AAb-ANT above controls. In immunoblots, AAb-ANT detected purified bovine heart ANT and GST-ANT1 and GST-ANT2 isoforms and, less frequently, the GST-ANT3 isoform. A construct lacking the last 146 amino acids did not react with AAb-ANT, indicating that the main epitopes are in the C-terminal 146 amino acids. Immunodetection of decapeptides covering this region shows that AAb-ANT detects at least three epitopes, demonstrating that ANT is the primary target of AAb-ANT. The most significant epitopes belong to the M2 and M3 hydrophilic loops of ANT suggesting that apart from being essential for its activity, these loops are highly immunogenic.
Manchado
Carlos
C
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Spain.
Orús
Josefina
J
Villarroya
Francesc
F
Roig
Eulalia
E
Heras
Magda
M
Giralt
Marta
M
Iglesias
Roser
R
Sanz
Ginés
G
Mampel
Teresa
T
Viñas
Octavi
O
D000818:Animals; D001324:Autoantigens / Q000276:immunology; D002311:Cardiomyopathy, Dilated / Q000201:enzymology / Q000276:immunology*; D002417:Cattle; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology / Q000378:metabolism; D000226:Mitochondrial ADP, ATP Translocases / Q000276:immunology*; D020033:Protein Isoforms; D051381:Rats; D011993:Recombinant Fusion Proteins
D001324:Autoantigens; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D000226:Mitochondrial ADP, ATP Translocases