Novel mechanisms of v-ATPase regulation in vertebrates

A subset of cellular compartments (organelles) maintain acidic interior environments that are critical for the specific functions of these organelles and for cell survival in general. Vacuolar H+-ATPase (v-ATPase) is energy-driven proton pump that acidifies intracellular compartments. It is a large assembly of 13+ proteins and hence difficult to study; its regulation (beyond subunit separation) is poorly understood despite decades of research. We will approach the question of v-ATPase regulation in vertebrates (most studies so far are done in yeast) through Rabconnectin-3a, a conserved brain-enriched protein whose mutations cause mental retardation, neuropathy and/or hearing loss. Little is known about Rabconnectin-3a due to its large size, lack of tools and early embryonic lethality. We generated those tools now, and detected Rabconnectin-3a on all organelles that acidify. I propose to study its role in the regulation of v-ATPase activity and organelle acidification, and to characterize its functions in health and disease.