title: Multiple vacuoles in impaired tonoplast trafficking3 mutants are independent organelles.
abstract: Plant vacuoles are essential and dynamic organelles, and mechanisms of vacuole biogenesis and fusion are not well characterized. We recently demonstrated that Wortmannin, an inhibitor of Phosphatidylinositol 3-Kinase (PI3K), induces the fusion of plant vacuoles both in roots of itt3/vti11 mutant alleles and in guard cells of wild type Arabidopsis and Fava bean. Here we used Fluorescence Recovery After Photobleaching (FRAP) to demonstrate that the vacuoles in itt3/vti11 are independent organelles. Furthermore, we used fluorescent protein reporters that bind specifically to Phosphatidylinositol 3-Phosphate (PtdIns(3)P) or PtdIns(4)P to show that Wortmannin treatments that induce the fusion of vti11 vacuoles result in the loss of PtdIns(3)P from cellular membranes. These results provided supporting evidence for a critical role of PtdIns(3)P in vacuole fusion in roots and guard cells.
authors.affiliation: a Department of Plant and Microbial Biology ; North Carolina State University ; Raleigh , NC USA.
authors.forename: Jiameng
authors.initials: J
authors.lastname: Zheng
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Han
authors.forename: Teun
authors.initials: T
authors.lastname: Munnik
authors.forename: Marcela
authors.initials: M
authors.lastname: Rojas-Pierce
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D059008:Time-Lapse Imaging; D014617:Vacuoles / Q000378:metabolism*; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; D000077191:Wortmannin
keywords: SNARE; Wortmannin; membrane fusion; phosphoinositides; vacuoles