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Light-dependent regulation of neurotransmitter release from rod photoreceptor ribbon synapses involves an interplay of Complexin 4 and Transducin with the SNARE complex

Authors :
Uwe Thorsten Lux
Jutta Meyer
Olaf Jahn
Adam Davison
Norbert Babai
Andreas Gießl
Anna Wartenberg
Heinrich Sticht
Nils Brose
Kerstin Reim
Johann Helmut Brandstätter
Source :
Frontiers in Molecular Neuroscience, Vol 17 (2024)
Publication Year :
2024
Publisher :
Frontiers Media S.A., 2024.

Abstract

Adaptation of photoreceptor sensitivity to varying light intensities is a fundamental requirement for retinal function and vision. Adaptive mechanisms in signal transduction are well described, but little is known about the mechanisms that adapt the photoreceptor synapse to changing light intensities. The SNARE complex regulators Complexin 3 and Complexin 4 have been proposed to be involved in synaptic light adaptation by limiting synaptic vesicle recruitment and fusion. How this Complexin effect is exerted is unknown. Focusing on rod photoreceptors, we established Complexin 4 as the predominant Complexin in the light-dependent regulation of neurotransmitter release. The number of readily releasable synaptic vesicles is significantly smaller in light than in dark at wildtype compared to Complexin 4 deficient rod photoreceptor ribbon synapses. Electrophysiology indicates that Complexin 4 reduces or clamps Ca2+-dependent sustained synaptic vesicle release, thereby enhancing light signaling at the synapse. Complexin 4 deficiency increased synaptic vesicle release and desensitized light signaling. In a quantitative proteomic screen, we identified Transducin as an interactor of the Complexin 4-SNARE complex. Our results provide evidence for a presynaptic interplay of both Complexin 4 and Transducin with the SNARE complex, an interplay that may facilitate the adaptation of synaptic transmission to light at rod photoreceptor ribbon synapses.

Details

Language :
English
ISSN :
16625099
Volume :
17
Database :
Directory of Open Access Journals
Journal :
Frontiers in Molecular Neuroscience
Publication Type :
Academic Journal
Accession number :
edsdoj.35cce0d7cb9b4c9d81e3effc86a79b21
Document Type :
article
Full Text :
https://doi.org/10.3389/fnmol.2024.1308466