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Synapsin and α-synuclein represent a growing list of condensate-forming proteins where the material states of condensates are directly linked to cellular functions (e.g., neurotransmission) and pathology (e.g., neurodegeneration). However, quantifying condensate material properties in living systems has been a significant challenge. To address this, we develop MAPAC (micropipette aspiration and whole-cell patch clamp), a platform that allows direct material quantification of condensates in live cells. We find 10,000-fold variations in the viscoelasticity of synapsin condensates, regulated by the partitioning of α-synuclein, a marker for synucleinopathies. Through in vitro reconstitutions, we identify 4 molecular factors that distinctly regulate the viscosity and interfacial tension of synapsin condensates, verifying the cellular effects of α-synuclein. Overall, our study provides unprecedented quantitative insights into the material properties of neuronal condensates and reveals a crucial role of α-synuclein in regulating condensate viscoelasticity. Furthermore, we envision MAPAC applicable to study a broad range of condensates in vivo. .
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http://dx.doi.org/10.1101/2024.07.28.605529 | DOI Listing |
EMBO J
August 2025
Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany.
Neuronal communication relies on precisely maintained synaptic vesicle (SV) clusters, which assemble via liquid-liquid phase separation. This process requires synapsins, the major synaptic phosphoproteins, which are known to bind actin. Reorganization of SVs, synapsins, and actin is a hallmark of synaptic activity, but the molecular details of the interactions between these components remain unclear.
View Article and Find Full Text PDFSci Adv
April 2025
Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
Synapsin and α-synuclein represent a growing list of condensate-forming proteins where the material states of condensates are directly linked to cellular functions (e.g., neurotransmission) and pathology (e.
View Article and Find Full Text PDFJ Mol Biol
April 2025
Laboratory of Molecular Neuroscience Berlin, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Univers
Multiple biomolecular condensates coexist at the pre- and post- synapse to enable vesicle dynamics and controlled neurotransmitter release in the brain. In pre-synapses, intrinsically disordered regions (IDRs) of synaptic proteins are drivers of condensation that enable clustering of synaptic vesicles (SVs). Using computational analysis, we show that the IDRs of SV proteins feature evolutionarily conserved non-random compositional biases and sequence patterns.
View Article and Find Full Text PDFTraffic
February 2025
Department of Anesthesiology, Department of Surgery, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China.
Phase separation is increasingly recognized as a paradigm to elucidate the self-assembly and organization of membrane-less bodies within the cell, which involves the segregation of a multi-component system into distinct phases with varying compositions and structures. The latest study has found that protein aggregates formed through phase separation can effectively realize short-distance transport of vesicles. PcloC responds to calcium through C2A domain-mediated calcium sensing, thereby extracting synaptic vesicles from the reserve pool where synaptic proteins aggregate into the surface of the active zone protein condensate.
View Article and Find Full Text PDFBiophys J
December 2024
Institut für Röntgenphysik, Göttingen, Germany. Electronic address:
Synaptic vesicle clusters or pools are functionally important constituents of chemical synapses. In the so-called reserve and the active pools, neurotransmitter-loaded synaptic vesicles (SVs) are stored and conditioned for fusion with the synaptic membrane and subsequent neurotransmitter release during synaptic activity. Vesicle clusters can be considered as so-called membraneless compartments, which form by liquid-liquid phase separation.
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