title: Homotypic vacuole fusion requires VTI11 and is regulated by phosphoinositides.
abstract: Most plant cells contain a large central vacuole that is essential to maintain cellular turgor. We report a new mutant allele of VTI11 that implicates the SNARE protein VTI11 in homotypic fusion of protein storage and lytic vacuoles. Fusion of the multiple vacuoles present in vti11 mutants could be induced by treatment with Wortmannin and LY294002, which are inhibitors of Phosphatidylinositol 3-Kinase (PI3K). We provide evidence that Phosphatidylinositol 3-Phosphate (PtdIns(3)P) regulates vacuole fusion in vti11 mutants, and that fusion of these vacuoles requires intact microtubules and actin filaments. Finally, we show that Wortmannin also induced the fusion of guard cell vacuoles in fava beans, where vacuoles are naturally fragmented after ABA-induced stomata closure. These results suggest a ubiquitous role of phosphoinositides in vacuole fusion, both during the development of the large central vacuole and during the dynamic vacuole remodeling that occurs as part of stomata movements.
authors.affiliation: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jiameng
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Han
authors.affiliation: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Rodriguez-Welsh
authors.affiliation: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA. Electronic address: mrojasp@ncsu.edu.
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 / Q000378:metabolism*; D002867:Chromones / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D050766:Qb-SNARE Proteins / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism*; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D029681:Arabidopsis Proteins; D002867:Chromones; D009025:Morpholines; D018129:Phosphatidylinositol Phosphates; D000081082:Phosphoinositide-3 Kinase Inhibitors; D050766:Qb-SNARE Proteins; C055525:phosphatidylinositol 3-phosphate; C120751:vesicle transport v-SNARE 11 protein, Arabidopsis; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D000077191:Wortmannin
keywords: SNARE; Wortmannin.; membrane fusion; phosphoinositides; vacuole