Detection of novel intracellular alpha-synuclein oligomeric species by fluorescence lifetime imaging.
Oligomerization and aggregation of alpha-synuclein molecules are believed to play a major role in neuronal dysfunction and loss in Parkinson's disease (PD) and dementia with Lewy bodies. However, alpha-synuclein oligomerization and aggregation have been detected only indirectly in cells using detergent extraction methods. Here, we show for the first time intracellular alpha-synuclein oligomerization using fluorescence lifetime imaging (FLIM). Two forms of alpha-synuclein homomeric interactions were detected: an antiparallel amino terminus-carboxyl terminus interaction between alpha-synuclein molecules, and a close amino terminus-carboxy terminus interaction within single alpha-synuclein molecules. Coexpression of the chaperone protein Hsp70, which can block alpha-synuclein toxicity in several systems, causes alpha-synuclein to adopt a different, open conformation, but Hsp70 does not alter alpha-synuclein-alpha-synuclein interactions. Thus, the neuroprotective effect of Hsp70 can be explained by its chaperone activity on alpha-synuclein molecules, rather than alteration of alpha-synuclein-alpha-synuclein interactions.
Klucken
Jochen
J
MassGeneral Institute for Neurodegenerative Disease, Alzheimer's Disease Research Unit, Massachusetts General Hospital, 114 16 St., Charlestown, MA 02129, USA.
Outeiro
Tiago F
TF
Nguyen
Paul
P
McLean
Pamela J
PJ
Hyman
Bradley T
BT
D045744:Cell Line, Tumor; D019281:Dimerization; D005910:Glioma / Q000473:pathology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D007834:Lasers; D008856:Microscopy, Fluorescence / Q000379:methods*; D018832:Molecular Chaperones; D011485:Protein Binding; D011487:Protein Conformation; D014162:Transfection; D051844:alpha-Synuclein / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity
D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones; D051844:alpha-Synuclein