| Autor: |
Rochet JC; Center for Neurologic Diseases, Brigham and Women's Hospital, Department of Neurology, Harvard Medical School, Cambridge, MA 02139, USA. rochet@pharmacy.purdue.edu, Outeiro TF, Conway KA, Ding TT, Volles MJ, Lashuel HA, Bieganski RM, Lindquist SL, Lansbury PT |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of molecular neuroscience : MN [J Mol Neurosci] 2004; Vol. 23 (1-2), pp. 23-34. |
| DOI: |
10.1385/jmn:23:1-2:023 |
| Abstrakt: |
Parkinson's disease (PD) is a neurologic disorder resulting from the loss of dopaminergic neurons in the brain. Two lines of evidence suggest that the protein alpha-synuclein plays a role in the pathogenesis of PD: Fibrillar alpha-synuclein is a major component of Lewy bodies in diseased neurons, and two mutations in alpha-synuclein are linked to early-onset disease. Accordingly, the fibrillization of alpha-synuclein is proposed to contribute to neurodegeneration in PD. In this report, we provide evidence that oligomeric intermediates of the alpha-synuclein fibrillization pathway, termed protofibrils, might be neurotoxic. Analyses of protofibrillar alpha-synuclein by atomic force microscopy and electron microscopy indicate that the oligomers consist of spheres, chains, and rings. alpha-Synuclein protofibrils permeabilize synthetic vesicles and form pore-like assemblies on the surface of brain-derived vesicles. Dopamine reacts with alpha-synuclein to form a covalent adduct that slows the conversion of protofibrils to fibrils. This finding suggests that cytosolic dopamine in dopaminergic neurons promotes the accumulation of toxic alpha-synuclein protofibrils, which might explain why these neurons are most vulnerable to degeneration in PD. Finally, we note that aggregation of alpha-synuclein likely occurs via different mechanisms in the cell versus the test tube. For example, the binding of alpha-synuclein to cellular membranes might influence its self-assembly. To address this point, we have developed a yeast model that might enable the selection of random alpha-synuclein mutants with different membrane-binding affinities. These variants might be useful to test whether membrane binding by alpha-synuclein is necessary for neurodegeneration in transgenic animal models of PD. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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