A synaptic F-actin network controls otoferlin-dependent exocytosis in auditory inner hair cells

Elife. 2015 Nov 14;4:e10988. doi: 10.7554/eLife.10988.

Abstract

We show that a cage-shaped F-actin network is essential for maintaining a tight spatial organization of Cav1.3 Ca(2+) channels at the synaptic ribbons of auditory inner hair cells. This F-actin network is also found to provide mechanosensitivity to the Cav1.3 channels when varying intracellular hydrostatic pressure. Furthermore, this F-actin mesh network attached to the synaptic ribbons directly influences the efficiency of otoferlin-dependent exocytosis and its sensitivity to intracellular hydrostatic pressure, independently of its action on the Cav1.3 channels. We propose a new mechanistic model for vesicle exocytosis in auditory hair cells where the rate of vesicle recruitment to the ribbons is directly controlled by a synaptic F-actin network and changes in intracellular hydrostatic pressure.

Keywords: actin network; cell biology; exocytosis; hair cell; mouse; neuroscience; osmotic pressure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • Animals
  • Exocytosis*
  • Hair Cells, Auditory, Inner / physiology*
  • Hydrostatic Pressure
  • Membrane Proteins / metabolism*
  • Mice, Inbred C57BL
  • Synapses / metabolism*

Substances

  • Actins
  • Membrane Proteins
  • otoferlin protein, mouse

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.