Comparison of Kinetics, Toxicity, Oligomer Formation, and Membrane Binding Capacity of α-Synuclein Familial Mutations at the A53 Site, Including the Newly Discovered A53V Mutation

Abstract

The involvement of α-synuclein (α-Syn) amyloid formation in Parkinson’s disease (PD) pathogenesis is supported by the discovery of α-Syn gene (SNCA) mutations linked with familial PD, which are known to modulate the oligomerization and aggregation of α-Syn. Recently, the A53V mutation has been discovered, which leads to late-onset PD. In this study, we characterized for the first time the biophysical properties of A53V, including the aggregation propensities, toxicity of aggregated species, and membrane binding capability, along with those of all familial mutations at the A53 position. Our data suggest that the A53V mutation accelerates fibrillation of α-Syn without affecting the overall morphology or cytotoxicity of fibrils compared to those of the wild-type (WT) protein. The aggregation propensity for A53 mutants is found to decrease in the following order: A53T > A53V > WT > A53E. In addition, a time course aggregation study reveals that the A53V mutant promotes early oligomerization similar to the case for the A53T mutation. It promotes the largest amount of oligomer formation immediately after dissolution, which is cytotoxic. Although in the presence of membrane-mimicking environments, the A53V mutation showed an extent of helix induction capacity similar to that of the WT protein, it exhibited less binding to lipid vesicles. The nuclear magnetic resonance study revealed unique chemical shift perturbations caused by the A53V mutation compared to those caused by other mutations at the A53 site. This study might help to establish the disease-causing mechanism of A53V in PD pathology.

Triphala inhibits alpha-synuclein fibrillization and their interaction study by NMR provides insights into the self-association of the protein

“…Now it is known that aSyn exists in oligomeric form during the lag phase of brillization process. 56,57,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74] So then a question arises that is the disappearance of peaks for stretches of residues in the free aSyn HSQC spectrum (Fig. 3A) due to the oligomerization of the protein?…”

Changes in the cellular fatty acid profile drive the proteasomal degradation of α‐synuclein and enhance neuronal survival

“…The A53T mutation is thought to accelerate the aggregation of α-synuclein and is thus considered to augment the pathogenicity of the protein. 38 Indeed, cPLA 2 inhibition in PC12 cells resulted in the limitation of A53T α-synuclein as indicated by immunoblotting analysis ( Figure 2C,D). To exclude the possibility that the GK200-induced α-synuclein reduction was an artefact from mere protein overexpression, we performed two sets of experiments.…”

Unraveling the aggregation dynamics of amyloidogenesis: A data-driven mathematical modeling approach

“…slower mutant like A53K, A53E and A30P, by performing simulation separately keeping the rate as ( = 0.08, for A53K), ( for A53E), and ( for = 0.5, = 3.0 = 0.07, = 0.04, = 2.5 = 0.01, = 0.005, = 0.1 A30P). (All other parameters are taken as given in Table S4 for the WT) For example, in case of mutant variants of -Synuclein, commonly known as A53V and A53T tend to accelerate the amyloid formation kinetics ( [44], [45], [46]), whereas, mutants such as A53K, A53E and A30P is known to behave in a completely opposite manner, elongating the amyloid formation kinetics ( [47], [45], [48], [46] Fig. 6A) and slower mutants (Fig.…”