title: Vac8p, an armadillo repeat protein, coordinates vacuole inheritance with multiple vacuolar processes.
abstract: Vac8p, an armadillo (ARM) repeat protein, is required for multiple vacuolar processes. It functions in vacuole inheritance, cytoplasm-to-vacuole protein targeting pathway, formation of the nucleus-vacuole junction and vacuole-vacuole fusion. These functions each utilize a distinct Vac8p-binding partner. Here, we report an additional Vac8p function: caffeine resistance. We show that Vac8p function in caffeine resistance is mediated via a newly identified Vac8p-binding partner, Tco89p. The interaction between Vac8p and each binding partner requires an overlapping subset of Vac8p ARM repeats. Moreover, these partners can compete with each other for access to Vac8p. Furthermore, Vac8p is enriched in three separate subdomains on the vacuole, each with a unique binding partner dedicated to a different vacuolar function. These findings suggest that a major role of Vac8p is to spatially separate multiple functions thereby enabling vacuole inheritance to occur concurrently with other vacuolar processes.
authors.affiliation: Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA. fxtang@ualr.edu
authors.forename: Fusheng
authors.initials: F
authors.lastname: Tang
authors.forename: Yutian
authors.initials: Y
authors.lastname: Peng
authors.forename: Johnathan J
authors.initials: JJ
authors.lastname: Nau
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Kauffman
authors.forename: Lois S
authors.initials: LS
authors.lastname: Weisman
mesh_terms: D002110:Caffeine / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D025141:Drug Resistance, Fungal / Q000502:physiology*; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D014617:Vacuoles / Q000502:physiology* / Q000648:ultrastructure; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D008074:Lipoproteins; D008565:Membrane Proteins; D010726:Phosphodiesterase Inhibitors; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; C485218:Tco89 protein, S cerevisiae; C472499:VAC17 protein, S cerevisiae; C111373:VAC8 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D002110:Caffeine