A Novel Neuron-Specific Regulator of the V-ATPase inDrosophila

Abstract

The V-ATPase is a highly conserved enzymatic complex that ensures appropriate levels of organelle acidification in virtually all eukaryotic cells. While the general mechanisms of this proton pump have been well studied, little is known about the specific regulations of neuronal V-ATPase. Here, we studied CG31030, a previously uncharacterized Drosophila protein predicted from its sequence homology to be part of the V-ATPase family. In contrast to its ortholog ATP6AP1/VhaAC45 which is ubiquitous, we observed that CG31030 expression is apparently restricted to all neurons, and using CRISPR/Cas9-mediated gene tagging, that it is mainly addressed to synaptic terminals. In addition, we observed that CG31030 is essential for fly survival and that this protein co-immunoprecipitates with identified V-ATPase subunits, and in particular ATP6AP2. Using a genetically-encoded pH probe (VMAT-pHluorin) and electrophysiological recordings at the larval neuromuscular junction, we show that CG31030 knockdown induces a major defect in synaptic vesicle acidification and a decrease in quantal size, which is the amplitude of the postsynaptic response to the release of a single synaptic vesicle.These defects were associated with severe locomotor impairments. Overall, our data indicate that CG31030, which we renamed VhaAC45-related protein (VhaAC45RP), is a specific regulator of neuronal V-ATPase in Drosophila that is required for proper synaptic vesicle acidification and neurotransmitter release.

The emerging role of furin in neurodegenerative and neuropsychiatric diseases

“…Furin-knockout β-cells show impaired cleavage of Ac45 [217]. Ac45 is ubiquitously expressed with the highest levels in neuronal and neuroendocrine cells and osteoclasts [218][219][220], and may be required for proper synaptic vesicle acidification and neurotransmitter release [221]. Ac45deficient patients not only have immunodeficiency, but also display a spectrum of neurocognitive abnormalities [222].…”

Drosophila as a Model Organism to Study Basic Mechanisms of Longevity

“…The following supporting information can be downloaded at: . References [ 283 , 284 , 285 , 286 , 287 , 288 , 289 , 290 , 291 , 292 , 293 , 294 , 295 , 296 , 297 , 298 , 299 , 300 , 301 ] are cited in the Supplementary Materials.…”