Density of GM1 in nanoclusters is a critical factor in the formation of a spherical assembly of amyloid β-protein on synaptic plasma membranes.
The deposition of amyloid β-protein (Aβ) is a pathological hallmark of Alzheimer's disease (AD). We previously found that the ganglioside-enriched microdomains (ganglioside clusters) in presynaptic neuronal membranes play a key role in the initiation of the Aβ assembly process. However, not all ganglioside clusters accelerate Aβ assembly. In the present study, we directly observed a spherical Aβ in an atomic force microscopic study on the morphology of a reconstituted lipid bilayer composed of lipids that were extracted from a detergent-resistant membrane microdomain (DRM) fraction of synaptosomes prepared from aged mouse brain. The Aβ assembly was generated on a distinctive GM1 domain, which was characterized as the Aβ-sensitive ganglioside nanocluster (ASIGN). By using an artificial GM1 cluster-binding peptide, ASIGN was found to have a high density of GM1; therefore, there would be a critical density of GM1 in nanoclusters to induce Aβ binding and assembly. These results suggest that ganglioside-bound Aβ (GAβ), which acts as an endogenous seed for Aβ fibril formation in AD brains, is generated on ASIGN on synaptosomal membranes.
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GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-N GENE-Y GENE-Y GENE-Y CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y GENE-Y GENE-Y GENE-Y
Aβ Aβ Aβ Aβ Aβ GM1 domain Aβ Aβ amyloid β-protein ganglioside ganglioside ganglioside ganglioside ganglioside Aβ Aβ Aβ amyloid β-protein