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Interplay between tau and α-synuclein liquid-liquid phase separation.

ABSTRACT: In Parkinson's disease with dementia, up to 50% of patients develop a high number of tau-containing neurofibrillary tangles. Tau-based pathologies may thus act synergistically with the α-synuclein pathology to confer a worse prognosis. A better understanding of the relationship between the two distinct pathologies is therefore required. Liquid-liquid phase separation (LLPS) of proteins has recently been shown to be important for protein aggregation involved in amyotrophic lateral sclerosis, whereas tau phase separation has been linked to Alzheimer's disease. We therefore investigated the interaction of α-synuclein with tau and its consequences on tau LLPS. We find α-synuclein to have a low propensity for both, self-coacervation and RNA-mediated LLPS at pH 7.4. However, full-length but not carboxy-terminally truncated α-synuclein efficiently partitions into tau/RNA droplets. We further demonstrate that Cdk2-phosphorylation promotes the concentration of tau into RNA-induced droplets, but at the same time decreases the amount of α-synuclein inside the droplets. NMR spectroscopy reveals that the interaction of the carboxy-terminal domain of α-synuclein with the proline-rich region P2 of tau is required for the recruitment of α-synuclein into tau droplets. The combined data suggest that the concentration of α-synuclein into tau-associated condensates can contribute to synergistic aSyn/tau pathologies.

SUBMITTER: Siegert A

PROVIDER: S-EPMC8197422 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:α-Synuclein (α-syn) is an intrinsically disordered protein (IDP) that undergoes liquid-liquid phase separation (LLPS), fibrillation, and forms insoluble intracellular Lewy’s bodies in neurons, which are the hallmark of Parkinson’s Disease (PD). Neurotoxicity precedes the formation of aggregates and is probably related to LLPS of α-syn in the cell. The molecular mechanisms underlying the early stages of LLPS are still elusive. To obtain structural insights into α-syn upon LLPS, we take advantage of cross-linking/mass spectrometry (XL-MS) and introduced an innovative new approach, termed COMPASS (COMPetitive PAiring StatisticS). COMPASS unravels transient interactions between α-syn molecules in liquid droplets to derive structural information of α-syn upon LLPS. In this work, we show that the conformational ensemble of α-syn shifts towards more elongated conformational states upon LLPS. We obtain insights into the critical initial stages of PD and establish a novel mass spectrometry-based approach that will aid to solve open questions in LLPS structural biology.

2024-03-18 | PXD033205 | Pride

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