title: V-ATPase-dependent luminal acidification is required for endocytic recycling of a yeast cell wall stress sensor, Wsc1p.
abstract: Wsc1p is a major cell wall sensor protein localized at the polarized cell surface. The localization of Wsc1p is maintained by endocytosis and recycling from endosomes back to the cell surface, but changes to the vacuole when cells are subjected to heat stress. Exploiting this unique property of Wsc1p, we screened for yeast single-gene deletion mutants exhibiting defects in Wsc1p trafficking. By expressing 3GFP-tagged Wsc1p in mutants with deleted genes whose function is related to intracellular trafficking, we identified 5 gene groups affecting Wsc1p trafficking, impaired respectively in endocytic internalization, multivesicular body sorting, the GARP complex, endosomal maturation/vacuolar fusion, and V-ATPase. Interestingly, deletion of the VPH1 gene, encoding the V(o) subunit of vacuolar-type H(+)-ATPase (V-ATPase), led to mis-localization of Wsc1p from the plasma membrane to the vacuole. In addition, disruption of other V-ATPase subunits (vma mutants) also caused defects of Wsc1p trafficking and vacuolar acidification similar to those seen in the vph1Δ mutant. Moreover, we found that deletion of the VPS26 gene, encoding a subunit of the retromer complex, also caused a defect in Wsc1p recycling and mis-localization of Wsc1p to the vacuole. These findings clarified the previously unidentified Wsc1p recycling pathway and requirement of V-ATPase-dependent luminal acidification for Wsc1p recycling.
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
authors: Kazuma
authors: K
authors: Ueno
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
authors: Mayu
authors: M
authors: Saito
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
authors: Makiko
authors: M
authors: Nagashima
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
authors: Ai
authors: A
authors: Kojima
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
authors: Show
authors: S
authors: Nishinoaki
authors: Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan. Electronic address: yama_jun@aoni.waseda.jp.
authors: Junko Y
authors: JY
authors: Toshima
authors: Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan. Electronic address: jtosiscb@rs.noda.tus.ac.jp.
authors: Jiro
authors: J
authors: Toshima
mesh_terms: D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism*; D013312:Stress, Physiological / Q000502:physiology*; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D025262:Vacuolar Proton-Translocating ATPases
keywords: ESCRT; Endocytosis; GARP; Golgi-associated retrograde protein; MVB; PVC; Recycling; Retromer complex; V-ATPase; VPS; Wsc1p; endosomal sorting complex required for transport; multivesicular body; prevacuolar compartment; vacuolar protein sorting