The vacuolar V-1/V-0-ATPase is involved in the release of the HOPS subunit Vps41 from vacuoles, vacuole fragmentation and fusion

Abstract

At yeast vacuoles, phosphorylation of the HOPS subunit Vps41 depends on the Yck3 kinase. In a screen for mutants that mimic the yck3 Delta phenotype, in which Vps41 accumulates in vacuolar dots, we observed that mutants in the V-0-part of the V-0/V-1-ATPase, in particular in vma16 Delta, also accumulate Vps41. This accumulation is not due to a phosphorylation defect, but to reduced release of Vps41 from vma16D vacuoles. One reason could be a connection to vacuole fission, which is blocked in V-ATPase mutants. Vacuole fusion is not impaired between vacuoles lacking the V-0-subunits Vma16 or Vma6 and wild-type vacuoles, whereas fusion between mutant vacuoles is reduced. Our data suggest a connection between vacuole biogenesis and membrane fusion. (C) 2008 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.