17 Lázaro, Diana F Amen, Triana Gerhardt, Ellen Song, Chengyuan Burns, Ryan Kruse, Niels Santos, Patrícia I Milovanovic, Dragomir Höglinger, Günter Mollenhauer, Brit Luk, Kelvin C Lee, Virginia My- Outeiro, Tiago AG Fischer AG Milovanovic (Berlin) Clinical Research (Munich) npj Parkinson's Disease npj Parkinson's Disease Springer Nature [London] 2373-8057 10.1038/s41531-025-01144-3 English 326 1 11 Alpha-synuclein (aSyn) is an intrinsically disordered protein involved in phase separation and several age-associated neurodegenerative disorders, including Parkinson's disease. However, its function and pathological role remain elusive. Here, we modeled different aSyn assemblies in living cells by exploiting its interaction with synphilin-1 (Sph1). We developed a model that reports on gel- and solid-like inclusions through coexpression of aSyn and Sph1. Distinct morphological differences emerged between VN-aSyn + aSyn-VC and VN-Sph1 + aSyn-VC assemblies, showing unique antibody recognition, proteinase K resistance, and protein mobilities. The VN-Sph1 + aSyn-VC interaction could be manipulated to alter inclusion size and number. These inclusions also contained lysosomes and AP-1 vesicles, aligning with observations in human brain tissue. Our study offers new insight into aSyn aggregation and release, highlighting the importance of Sph1 and other aSyn-interacting proteins in synucleinopathies, which involve diverse copathologies only now beginning to be understood. PUB:(DE-HGF)16, ; 0, ; Journal Article 2025 DZNE-2025-01297 2025 pmc:PMC12635182 pmid:41266386 https://pub.dzne.de/record/282474 https://doi.org/10.1038/s41531-025-01144-3