Mitochondrial localization of alpha-synuclein protein in alpha-synuclein overexpressing cells.
Alpha-synuclein (alpha-syn) is implicated in the pathogenesis of Parkinson's disease (PD). Mutations in alpha-syn gene or alpha-syn locus (SNCA) triplication are associated with mitochondrial abnormalities and early onset of familial PD. The goals of the present study were to examine whether alpha-syn is localized in the mitochondria of alpha-syn overexpressing cells (HEK-syn cells); and whether alpha-syn overexpression causes cells to be more vulnerable to mitochondrial toxin, rotenone. Western blotting and confocal microscopy techniques were employed to assess localization of alpha-syn in the mitochondria of HEK-293 cells that were stably transfected with human wild-type alpha-syn. The results demonstrated that the mitochondrial fractions that were isolated from HEK-syn cells showed the presence of alpha-syn, whereas, no alpha-syn was detected in the mitochondrial fractions of control HEK cells. The mitochondria of HEK-syn cells were found to be more susceptible to rotenone-induced toxicity when compared to control HEK cells. The intracellular ATP levels were significantly decreased in HEK-syn cells in response to sub toxic concentrations of rotenone. These results suggest that under overexpression conditions, alpha-syn may translocate to mitochondria and cause enhanced toxicity in response to sub toxic concentrations of mitochondrial toxins. This study has implications to the pathogenesis of familial PD where alpha-syn overexpression is mainly involved.
Department of Pathology, University of North Dakota, School of Medicine and Health Sciences, 501 North Columbia Road,Grand Forks, ND 58202, USA. sshavali@medicine.nodak.edu
Shaik
S
Shavali
Holly M
HM
Brown-Borg
Manuchair
M
Ebadi
James
J
Porter
D000255:Adenosine Triphosphate / Q000378:metabolism; D000704:Analysis of Variance; D002461:Cell Line, Transformed; D051545:Cyclooxygenase 1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007306:Insecticides / Q000494:pharmacology; D018613:Microscopy, Confocal / Q000379:methods; D008928:Mitochondria / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology; D014162:Transfection / Q000379:methods; D051844:alpha-Synuclein / Q000378:metabolism*
D007306:Insecticides; D051844:alpha-Synuclein; D012402:Rotenone; D000255:Adenosine Triphosphate; D051545:Cyclooxygenase 1