title: The signaling lipid PI(3,5)P₂ stabilizes V₁-V(o) sector interactions and activates the V-ATPase.
abstract: Vacuolar proton-translocating ATPases (V-ATPases) are highly conserved, ATP-driven proton pumps regulated by reversible dissociation of its cytosolic, peripheral V1 domain from the integral membrane V(o) domain. Multiple stresses induce changes in V1-V(o) assembly, but the signaling mechanisms behind these changes are not understood. Here we show that certain stress-responsive changes in V-ATPase activity and assembly require the signaling lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). V-ATPase activation through V1-V(o) assembly in response to salt stress is strongly dependent on PI(3,5)P2 synthesis. Purified V(o) complexes preferentially bind to PI(3,5)P2 on lipid arrays, suggesting direct binding between the lipid and the membrane sector of the V-ATPase. Increasing PI(3,5)P2 levels in vivo recruits the N-terminal domain of V(o)-sector subunit Vph1p from cytosol to membranes, independent of other subunits. This Vph1p domain is critical for V1-V(o) interaction, suggesting that interaction of Vph1p with PI(3,5)P2-containing membranes stabilizes V1-V(o) assembly and thus increases V-ATPase activity. These results help explain the previously described vacuolar acidification defect in yeast fab1 and vac14 mutants and suggest that human disease phenotypes associated with PI(3,5)P2 loss may arise from compromised V-ATPase stability and regulation.
authors: Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13219 Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI 48109.
authors: Sheena Claire
authors: SC
authors: Li
authors: Theodore T
authors: TT
authors: Diakov
authors: Tao
authors: T
authors: Xu
authors: Maureen
authors: M
authors: Tarsio
authors: Wandi
authors: W
authors: Zhu
authors: Sergio
authors: S
authors: Couoh-Cardel
authors: Lois S
authors: LS
authors: Weisman
authors: Patricia M
authors: PM
authors: Kane
mesh_terms: D008565:Membrane Proteins / Q000235:genetics; D009997:Osmotic Pressure; D018129:Phosphatidylinositol Phosphates / Q000235:genetics / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D015398:Signal Transduction; D012965:Sodium Chloride / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000096:biosynthesis*
chemical_list: D008565:Membrane Proteins; D018129:Phosphatidylinositol Phosphates; D029701:Saccharomyces cerevisiae Proteins; C452435:VAC14 protein, S cerevisiae; C106336:phosphatidylinositol 3,5-diphosphate; D012965:Sodium Chloride; C095504:FAB1 protein, S cerevisiae; D017853:Phosphotransferases (Alcohol Group Acceptor); D025262:Vacuolar Proton-Translocating ATPases