Mutant and wild-type alpha-synuclein interact with mitochondrial cytochrome C oxidase.
Alpha-synuclein, a presynaptic protein, was found to be the major component in the Lewy bodies (LB) in both inherited and sporadic Parkinson's disease (PD). Furthermore, rare mutations of alpha-synuclein cause autosomal-dominant PD. However, it is unknown how alpha-synuclein is involved in the pathogenesis of nigral degeneration in PD. In this study, we examine the protein-protein interactions of wild-type and mutant (A53T) a-synuclein with adult human brain cDNA expression library using the yeast two-hybrid technique. We found that both normal and mutant alpha-synuclein specifically interact with the mitochondrial complex IV enzyme, cytochrome C oxidase (COX). Wild-type and mutant alpha-synuclein genes were further fused with c-Myc tag and translated in rabbit reticulocyte lysate. Using anti-c-Myc antibody, we demonstrated that both wild-type and mutant alpha-synuclein, coimmunoprecipitated with COX. We also showed that potassium cyanide, a selective COX inhibitor, synergistically enhanced the sensitivity of SH-SY5Y neuroblastoma cells to dopamine-induced cell death. In conclusion, we found specific protein-protein interactions of alpha-synuclein, a major LB protein, to COX, a key enzyme of the mithochondrial respiratory system. This interaction suggests that alpha-synuclein aggregation may contribute to enhance the mitochondrial dysfunction, which might be a key factor in the pathogenesis of PD.
Elkon
Hanock
H
Felsenstein Medical Research Center, Department of Clinical Biochemistry, Sackler School of Medicine, Tel-Aviv University, Petah-Tikva, Israel.
Don
Jermy
J
Melamed
Eldad
E
Ziv
Ilan
I
Shirvan
Anat
A
Offen
Daniel
D
D000328:Adult; D001483:Base Sequence; D004298:Dopamine / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D010300:Parkinson Disease / Q000378:metabolism*; D011190:Potassium Cyanide / Q000378:metabolism; D011485:Protein Binding; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D051843:Synucleins; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D051844:alpha-Synuclein
D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; D016271:Proto-Oncogene Proteins c-myc; C497604:SNCA protein, human; D051843:Synucleins; D051844:alpha-Synuclein; D003576:Electron Transport Complex IV; D011190:Potassium Cyanide; D004298:Dopamine