Slow kinesin-dependent microtubular transport facilitates ribbon synapse assembly in developing cochlear inner hair cells

• DOI: 10.7554/elife.98145.1
• Publication Date: 2024-06-28T13:50:04Z
• Authors: Roos Anouk Voorn; Michael Sternbach; Amandine Jarysta; Vladan Rankovic; Basile Tarchini; Fred Wolf; Christian Vogl
• Keywords: Ribbon synapse; Kinesin

Sensory synapses are characterized by electron-dense presynaptic specializations, so-called synaptic ribbons. In cochlear inner hair cells (IHCs), ribbons play an essential role as core active zone (AZ) organizers, where they tether vesicles, cluster calcium channels and facilitate the temporally-precise release of primed vesicles. While a multitude studies aimed to elucidate molecular composition function IHC ribbon synapses, developmental formation these signalling complexes remains largely elusive date. To address this shortcoming, we performed long-term live-cell imaging fluorescently-labelled precursors in young postnatal IHCs track precursor motion. We show that utilize apico-basal microtubular (MT) cytoskeleton for targeted trafficking presynapse, process reminiscent slow axonal transport neurons. During translocation, volume regulation is achieved highly dynamic structural plasticity – regularly-occurring fusion fission events. Pharmacological MT destabilization negatively impacted on translocation attenuated plasticity, whereas genetic disruption anterograde motor Kif1a impaired accumulation during maturation. Combined, our data thus indicate adequate synapse maintenance.