Morphology and intervesicle distances in condensates of synaptic vesicles and synapsin.

Autor:	Neuhaus C; Institut für Röntgenphysik, Göttingen, Germany., Alfken J; Institut für Röntgenphysik, Göttingen, Germany., Frost J; Institut für Röntgenphysik, Göttingen, Germany., Matthews L; The European Synchrotron Radiation Facility, Grenoble, France., Hoffmann C; Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany., Ganzella M; Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany., Milovanovic D; Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany., Salditt T; Institut für Röntgenphysik, Göttingen, Germany. Electronic address: tsaldit@gwdg.de.
Jazyk:	angličtina
Zdroj:	Biophysical journal [Biophys J] 2024 Nov 08. Date of Electronic Publication: 2024 Nov 08.
DOI:	10.1016/j.bpj.2024.11.004
Abstrakt:	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. Synapsin as one of the most abundant synaptic proteins has been identified as a major driver of pool formation. It has been shown to induce liquid-liquid phase separation and form condensates on its own in solution, but also has been shown to integrate vesicles into condensates in vitro. In this process, the intrinsically disordered region of synapsin is believed to play a critical role. Here, we first investigate the solution structure of synapsin and SVs separately by small-angle x-ray scattering. In the limit of low momentum transfer q, the scattering curve for synapsin gives clear indication for supramolecular aggregation (condensation). We then study mixtures of SVs and synapsin-forming condensates, aiming at the morphology and intervesicle distances, i.e., the structure of the condensates in solution. To obtain the structure factor S(q) quantifying intervesicle correlation, we divide the scattering curve of condensates by that of pure SV suspensions. Analysis of S(q) in combination with numerical simulations of cluster aggregation indicates a noncompact fractal-like vesicular fluid with rather short intervesicle distances at the contact sites. Competing Interests: Declaration of interests The authors declare no competing interests. (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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