Structure-Function Analysis of a Neuron-Specific Vesicular ATPase in Neurotransmission

Abstract

Neurotransmission is central to neuronal communication, through which information is processed, stored, and retrieved. The vesicular ATPase (V-ATPase) protein is a proton pump that is implicated in neurotransmission. It acidifies synaptic vesicles to be consequently loaded with neurotransmitters prior to release through exocytosis. V100 is a neuron-specific vesicular ATPase subunit a1, and it is a major subunit that determines where the vesicular ATPase functions intracellularly. Previous studies characterized two putative functions for the V100 in neuronal cell biology; intracellular vesicle acidification, and membrane fusion. In this project, we set out to dissect the function of V100 genetically - using immunolabeling and electrophysiology- to understand acidification-dependent and -independent functions. The results cast some light on a potential regulation of the V100 by Ca2+/Calmodulin. This regulatory mechanism may be specifically required for spontaneous vesicle release independent of the proton pump function of the V-ATPase.