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

PFY Vincent, Y Bouleau, C Petit, D Dulon - Elife, 2015 - elifesciences.org
Elife, 2015elifesciences.org
We show that a cage-shaped F-actin network is essential for maintaining a tight spatial
organization of Cav1. 3 Ca2+ 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 …
We show that a cage-shaped F-actin network is essential for maintaining a tight spatial organization of Cav1.3 Ca2+ 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.
DOI: http://dx.doi.org/10.7554/eLife.10988.001
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