Number and Brightness analysis of alpha-synuclein oligomerization and the associated mitochondrial morphology alterations in live cells

Plotegher, Nicoletta; Gratton, Enrico; Bubacco, Luigi

doi:10.1016/j.bbagen.2014.02.013

Cited by 80 publications

(78 citation statements)

References 64 publications

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“…Therefore, it is possible that the oligomers characterized here represent the same initial subset of oligomers prior to their reorganization. In vivo, oligomers characterized recently by number and brightness analysis in live SH-SH5Y cells also show a similar size range encompassing maximum 6 + − 4-mers, similar to our observations [50]. α-Syn is known to co-populate a range of conformational states as observed by ESI-IMS-MS. Our previous ESI-IMS-MS analysis of wild-type α-syn revealed a primarily extended population (∼2482 + − 159 Å) and a subpopulation of two compact conformational series (∼1851 + − 276 Å) with multiple overlapping features and a less observable dimeric species under native conditions [37] in accordance with previously published research [34].…”

Section: Discussionsupporting

confidence: 90%

Distinct higher-order α-synuclein oligomers induce intracellular aggregation

Illes‐Toth

Ramos

Cappai

et al. 2015

Biochemical Journal

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Misfolding and aggregation of α-synuclein (α-syn) into Lewy bodies is associated with a range of neurological disorders, including Parkinson's disease (PD). The cell-to-cell transmission of α-syn pathology has been linked to soluble amyloid oligomer populations that precede Lewy body formation. Oligomers produced in vitro under certain conditions have been demonstrated to induce intracellular aggregation in cell culture models. In the present study, we characterize, by ESI-ion mobility spectrometry (IMS)-MS, a specific population of α-syn oligomers. These MS-compatible oligomers were compared with oligomers with known seeding and pore-forming capabilities and were shown to have the ability to induce intracellular aggregation. Each oligomer type was shown to have distinct epitope profiles that correlated with their toxic gain-of-function. Structurally, the MS compatible oligomers populated a range of species from dimers through to hexamers. Lower-order oligomers were structurally diverse and consistent with unstructured assemblies. Higher-order oligomers were shown to be compact with ring-like structures. The observation of this compact state may explain how this natively disordered protein is able to transfer pathology from cell to cell and avoid degradation by cellular proteases.

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Section: Discussionsupporting

confidence: 90%

Distinct higher-order α-synuclein oligomers induce intracellular aggregation

Illes‐Toth

Ramos

Cappai

et al. 2015

Biochemical Journal

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“…N&B analysis was carried out in order to obtain information about the apparent oligomerization state of mRFP-Lact-C2 (49)(50)(51)(52). Since mRFP-Lact-C2 binds specifically to PS, the presence of PS-rich platforms (i.e., capable of binding more than one mRFPLact-C2 molecule) should be evident as an increased apparent multimerization of the protein (i.e., more mRFP-Lact-C2 molecules diffusing together as a single unit).…”

Section: Resultsmentioning

confidence: 99%

Phosphatidylserine Lateral Organization Influences the Interaction of Influenza Virus Matrix Protein 1 with Lipid Membranes

Bobone

Hilsch

Storm

et al. 2017

J Virol

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Influenza A virus matrix protein 1 (M1) is an essential component involved in the structural stability of the virus and in the budding of new virions from infected cells. A deeper understanding of the molecular basis of virion formation and the budding process is required in order to devise new therapeutic approaches. We performed a detailed investigation of the interaction between M1 and phosphatidylserine (PS) (i.e., its main binding target at the plasma membrane [PM]), as well as the distribution of PS itself, both in model membranes and in living cells. To this end, we used a combination of techniques, including Förster resonance energy transfer (FRET), confocal microscopy imaging, raster image correlation spectroscopy, and number and brightness (N&B) analysis. Our results show that PS can cluster in segregated regions in the plane of the lipid bilayer, both in model bilayers constituted of PS and phosphatidylcholine and in living cells. The viral protein M1 interacts specifically with PS-enriched domains, and such interaction in turn affects its oligomerization process. Furthermore, M1 can stabilize PS domains, as observed in model membranes. For living cells, the presence of PS clusters is suggested by N&B experiments monitoring the clustering of the PS sensor lactadherin. Also, colocalization between M1 and a fluorescent PS probe suggest that, in infected cells, the matrix protein can specifically bind to the regions of PM in which PS is clustered. Taken together, our observations provide novel evidence regarding the role of PS-rich domains in tuning M1-lipid and M1-M1 interactions at the PM of infected cells.IMPORTANCE Influenza virus particles assemble at the plasma membranes (PM) of infected cells. This process is orchestrated by the matrix protein M1, which interacts with membrane lipids while binding to the other proteins and genetic material of the virus. Despite its importance, the initial step in virus assembly (i.e., M1-lipid interaction) is still not well understood. In this work, we show that phosphatidylserine can form lipid domains in physical models of the inner leaflet of the PM. Furthermore, the spatial organization of PS in the plane of the bilayer modulates M1-M1 interactions. Finally, we show that PS domains appear to be present in the PM of living cells and that M1 seems to display a high affinity for them.KEYWORDS influenza, assembly, confocal microscopy, fluorescence image analysis, lipid rafts, matrix protein, model membranes, phosphatidylserine, plasma membrane I nfluenza A virus (IAV) is a major burden to human health and remains a prominent cause of mortality worldwide (1, 2). Despite significant research efforts, detailed knowledge about the molecular mechanisms involved in IAV infection is still limited. A deeper understanding of the virus machinery and its interaction with the host is

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“…Deeply, according to the information above, the mitochondrial dysfunction exists both in α-syn overexpression models and in CTIQs treated models [25,38,46,47,49,50,65,66,78,82,[137][138][139][140]. Therefore, the contribution of α-syn and CTIQs to the pathogenesis of PD could both ascribe to the damaged mitochondria, which further verified the interrelation between CTIQs and α-syn.…”

Section: Ctiqs and α-Syn Aggregationmentioning

confidence: 91%

“…Many mitochondria exist in the synapses of Dopaminergic neurons, the impairment of which is an initial step for cell apoptosis. In this mechanism, aggregated α-syn can interact with mitochondrial membranes and further induce the release of respiratory protein cytochrome c, an increase of mitochondrial calcium, complex I dysfunction, a decrease of membrane potential and mitochondrial swelling, finally leading to the mitochondrial dysfunction [137][138][139][140]. And mitochondrial dysfunction can generate the excessive ROS and eventually induce death of dopaminergic neuron [141].…”

Section: α-Synuclein Aggregation and Parkinson Diseasementioning

confidence: 99%