{"doi":"10.1002/pro.70195","title":"Amyloid formation of alternatively spliced variants of α‐synuclein","abstract":"Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy are disorders characterized by the presence of cytosolic α-synuclein (SNCA) amyloids. The gene SNCA is alternatively spliced, generating three variants of SNCA, missing exon 3 (SNCAΔ3) or 5 (SNCAΔ5), or both exons (SNCAΔ3Δ5). Despite purported upregulation in disease states, their pathological relevance is ill-defined. Here, we investigated the amyloid formation of alternatively spliced variants under physiological conditions. Aggregation kinetics, secondary structure, and fibril morphology of N-terminally acetylated SNCAΔ3, SNCAΔ5, and SNCAΔ3Δ5 were assessed by thioflavin-T fluorescence, circular dichroism spectroscopy, and transmission electron microscopy, respectively. Compared to SNCA, both SNCAΔ5 and SNCAΔ3Δ5 aggregate faster and adopt a more twisted fibril morphology, whereas SNCAΔ3 is more sensitive to solution conditions, exhibiting similar or modestly faster aggregation kinetics compared to SNCA. Cross-seeding experiments using spliced-variant fibrils and soluble SNCA showed that despite fibril morphological differences, SNCAΔ5 were competent seeds for SNCA, which is explained by their similar protease-K resistant regions. Contrastingly, neither SNCAΔ3 nor SNCAΔ3Δ5 fibrils cross-seed SNCA, indicating exon 3 (residues 41-54) is essential in modulating fibril structure. Notably, SNCA aggregation is stimulated by sub-stoichiometric amounts of soluble SNCAΔ5 and SNCAΔ3Δ5, but not SNCAΔ3, suggesting that exon 5 (residues 103-130) is more important in modulating aggregation kinetics. Taken together, we propose that alternatively spliced variants are pathogenic by exacerbating aggregation of the main SNCA isoform.","journal":"Protein Science","year":2025,"id":533908,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9593,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":373427,"name":"Ryan P. McGlinchey","orcid":"0000-0003-3072-3843","position":1,"is_corresponding":false},{"id":297793,"name":"Jennifer C. Lee","orcid":"0000-0003-0506-8349","position":2,"is_corresponding":false},{"id":1416527,"name":"Daniel Q. SanGiovanni","orcid":null,"position":0,"is_corresponding":true}],"reference_count":64,"raw_metadata":null,"created_at":"2026-07-19T02:51:43.451278Z","pmid":"40522183","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}