α-Synuclein (α-Syn) aggregation is closely associated with Parkinson’s disease neuropathology. Physiologically, α-Syn promotes synaptic vesicle (SV) clustering and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly. However, the underlying structural and molecular mechanisms are uncertain and it is not known whether this function affects the pathological aggregation of α-Syn. Here we show that the juxtamembrane region of vesicle-associated membrane protein 2 (VAMP2)—a component of the SNARE complex that resides on SVs—directly interacts with the carboxy-terminal region of α-Syn through charged residues to regulate α-Syn’s function in clustering SVs and promoting SNARE complex assembly by inducing a multi-component condensed phase of SVs, α-Syn and other components. Moreover, VAMP2 binding protects α-Syn against forming aggregation-prone oligomers and fibrils in these condensates. Our results suggest a molecular mechanism that maintains α-Syn’s function and prevents its pathological amyloid aggregation, the failure of which may lead to Parkinson’s disease.

α-突触核蛋白 (α-Syn) 聚集与帕金森病神经病理学密切相关。从生理学角度来看，α-Syn 促进突触小泡 (SV) 聚集和可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体 (SNARE) 复合物组装。然而，潜在的结构和分子机制尚不清楚，并且尚不清楚该功能是否影响α-Syn的病理聚集。在这里，我们发现囊泡相关膜蛋白 2 (VAMP2) 的近膜区域（驻留在 SV 上的 SNARE 复合物的一个组成部分）通过带电残基直接与 α-Syn 的羧基末端区域相互作用，以调节 α-Syn 的功能通过诱导 SV、α-Syn 和其他组分的多组分凝聚相，对 SV 进行聚类并促进 SNARE 复合物组装。此外，VAMP2 结合可保护 α-Syn 免于在这些凝聚物中形成易于聚集的寡聚物和原纤维。我们的研究结果表明，存在一种维持 α-Syn 功能并防止其病理性淀粉样蛋白聚集的分子机制，这种聚集的失败可能导致帕金森病。