Rabconnectin3alpha promotes stable activity of the H+ pump on synaptic vesicles in hair cells
- Authors
- Einhorn, Z., Trapani, J.G., Liu, Q., and Nicolson, T.
- ID
- ZDB-PUB-120813-5
- Date
- 2012
- Source
- The Journal of neuroscience : the official journal of the Society for Neuroscience 32(32): 11144-11156 (Journal)
- Registered Authors
- Einhorn, Zev, Liu, Qianyong, Nicolson, Teresa, Trapani, Josef
- Keywords
- none
- MeSH Terms
-
- Acoustic Stimulation/adverse effects
- Action Potentials/genetics
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism*
- Analysis of Variance
- Animals
- Animals, Genetically Modified
- Enzyme Inhibitors/pharmacology
- Escape Reaction/drug effects
- Escape Reaction/physiology
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Hair Cells, Auditory/cytology*
- Larva
- Lateral Line System/metabolism
- Macrolides/pharmacology
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Microscopy, Confocal
- Molecular Biology
- Mutation/genetics
- Physical Stimulation
- Proton Pumps/metabolism*
- RNA, Messenger/metabolism
- Sensation Disorders/genetics
- Synaptic Vesicles/drug effects
- Synaptic Vesicles/metabolism*
- Vacuolar Proton-Translocating ATPases/metabolism
- Video Recording
- Vision Disorders/genetics
- Zebrafish
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
- PubMed
- 22875945 Full text @ J. Neurosci.
Acidification of synaptic vesicles relies on the vacuolar-type ATPase (V-ATPase) and provides the electrochemical driving force for neurotransmitter exchange. The regulatory mechanisms that ensure assembly of the V-ATPase holoenzyme on synaptic vesicles are unknown. Rabconnectin3α (Rbc3α) is a potential candidate for regulation of V-ATPase activity because of its association with synaptic vesicles and its requirement for acidification of intracellular compartments. Here, we provide the first evidence for a role of Rbc3α in synaptic vesicle acidification and neurotransmission. In this study, we characterized mutant alleles of rbc3α isolated from a large-scale screen for zebrafish with auditory/vestibular defects. We show that Rbc3α is localized to basal regions of hair cells in which synaptic vesicles are present. To determine whether Rbc3α regulates V-ATPase activity, we examined the acidification of synaptic vesicles and localization of the V-ATPase in hair cells. In contrast to wild-type hair cells, we observed that synaptic vesicles had elevated pH, and a cytosolic subunit of the V-ATPase was no longer enriched in synaptic regions of mutant hair cells. As a consequence of defective acidification of synaptic vesicles, afferent neurons in rbc3α mutants had reduced firing rates and reduced accuracy of phase-locked action potentials in response to mechanical stimulation of hair cells. Collectively, our data suggest that Rbc3α modulates synaptic transmission in hair cells by promoting V-ATPase activity in synaptic vesicles.