Mutations in the Tulp1 gene cause severe, early-onset retinitis pigmentosa (RP14) in humans. In the retina, Tulp1 is mainly expressed in photoreceptors that use ribbon synapses to communicate with the inner retina. In the present study, we demonstrate that Tulp1 is highly enriched in the periactive zone of photoreceptor presynaptic terminals where Tulp1 colocalizes with major endocytic proteins close to the synaptic ribbon. Analyses of Tulp1 knock-out mice demonstrate that Tulp1 is essential to keep endocytic proteins enriched at the periactive zone and to maintain high levels of endocytic activity close to the synaptic ribbon. Moreover, we have discovered a novel interaction between Tulp1 and the synaptic ribbon protein RIBEYE, which is important to maintain synaptic ribbon integrity. The current findings suggest a new model for Tulp1-mediated localization of the endocytic machinery at the periactive zone of ribbon synapses and offer a new rationale and mechanism for vision loss associated with genetic defects in Tulp1.
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http://dx.doi.org/10.1523/JNEUROSCI.2275-15.2016 | DOI Listing |
J Mol Cell Biol
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Synaptic Neuroscience Team, Department of Neurosurgery, University Hospital Bonn, Bonn 53127, Germany.
Synaptic vesicles can undergo several modes of exocytosis, endocytosis, and trafficking within individual synapses, and their fates may be linked to different vesicular protein compositions. Here, we mapped the intrasynaptic distribution of the synaptic vesicle proteins SV2B and SV2A in glutamatergic synapses of the hippocampus using three-dimensional electron microscopy. SV2B was almost completely absent from docked vesicles and a distinct cluster of vesicles found near the active zone.
View Article and Find Full Text PDFAutophagy
October 2023
Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
In neuronal synapses, autophagosome biogenesis is coupled with the activity-dependent synaptic vesicle cycle via ATG-9. How vesicles containing ATG-9 are sorted at the presynapse is unknown. We performed forward genetic screens at single synapses of neurons for mutants that disrupt ATG-9 presynaptic localization, and identified the long isoform of the active zone protein CLA-1 (Clarinet; CLA-1 L).
View Article and Find Full Text PDFPLoS Biol
April 2023
Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America.
Autophagy is essential for cellular homeostasis and function. In neurons, autophagosome biogenesis is temporally and spatially regulated to occur near presynaptic sites, in part via the trafficking of autophagy transmembrane protein ATG-9. The molecules that regulate autophagy by sorting ATG-9 at synapses remain largely unknown.
View Article and Find Full Text PDFBiol Chem
April 2023
Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch Strasse 31, D-48149, Münster, Germany.
Mol Biol Cell
May 2023
Department of Biology, Brandeis University, Waltham, MA 02453.
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