title: The Ca2+ pump inhibitor, thapsigargin, inhibits root gravitropism in Arabidopsis thaliana.
abstract: Thapsigargin, a specific inhibitor of most animal intracellular SERCA-type Ca2+ pumps present in the sarcoplasmic/endoplasmic reticulum, was originally isolated from the roots of the Mediterranean plant Thapsia gargancia L. Here, we demonstrate that this root-derived compound is capable of altering root gravitropism in Arabidopsis thaliana. Thapsigargin concentrations as low as 0.1 microM alter root gravitropism whereas under similar conditions cyclopiazonic acid does not. Furthermore, a fluorescently conjugated thapsigargin (BODIPY FL thapsigargin) suggests that target sites for thapsigargin are located in intracellular organelles in the root distal elongation zone and the root cap, regions known to regulate root gravitropism.
authors.affiliation: Millennium Nucleus in Plant Cell Biology and Centro de Biotecnología Vegetal, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Urbina
authors.forename: Herman
authors.initials: H
authors.lastname: Silva
authors.forename: Lee A
authors.initials: LA
authors.lastname: Meisel
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018522:Gravitropism / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D019284:Thapsigargin / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases