ZFIN ID: ZDB-PUB-160614-9
Synaptic Ribbons Require Ribeye for Electron Density, Proper Synaptic Localization, and Recruitment of Calcium Channels
Lv, C., Stewart, W.J., Akanyeti, O., Frederick, C., Zhu, J., Santos-Sacchi, J., Sheets, L., Liao, J.C., Zenisek, D.
Date: 2016
Source: Cell Reports   15(12): 2784-95 (Journal)
Registered Authors: Frederick, Courtney, Lv, Caixia, Sheets, Lavinia, Zenisek, David, Zhu, Jie
Keywords: exocytosis, hair cell, hearing, retina, synaptic ribbon, vestibular system
MeSH Terms:
  • Animals
  • Calcium Channels/metabolism*
  • Electric Capacitance
  • Electrons*
  • Exocytosis
  • Eye Proteins/metabolism*
  • Hair Cells, Auditory/metabolism
  • Homozygote
  • Ion Channel Gating
  • Mutation/genetics
  • Nerve Tissue Proteins/metabolism*
  • Neurons, Afferent/metabolism
  • Patch-Clamp Techniques
  • Photoreceptor Cells, Vertebrate/metabolism
  • Photoreceptor Cells, Vertebrate/ultrastructure
  • Synapses/metabolism*
  • Synapses/ultrastructure
  • Zebrafish/metabolism*
  • Zebrafish Proteins/metabolism*
PubMed: 27292637 Full text @ Cell Rep.
Synaptic ribbons are structures made largely of the protein Ribeye that hold synaptic vesicles near release sites in non-spiking cells in some sensory systems. Here, we introduce frameshift mutations in the two zebrafish genes encoding for Ribeye and thus remove Ribeye protein from neuromast hair cells. Despite Ribeye depletion, vesicles collect around ribbon-like structures that lack electron density, which we term "ghost ribbons." Ghost ribbons are smaller in size but possess a similar number of smaller vesicles and are poorly localized to synapses and calcium channels. These hair cells exhibit enhanced exocytosis, as measured by capacitance, and recordings from afferent neurons post-synaptic to hair cells show no significant difference in spike rates. Our results suggest that Ribeye makes up most of the synaptic ribbon density in neuromast hair cells and is necessary for proper localization of calcium channels and synaptic ribbons.