title: Arabidopsis actin-depolymerizing factors (ADFs) 1 and 9 display antagonist activities.
abstract: We provide evidence that one of the 11 Arabidopsis actin-depolymerizing factors (ADFs), namely ADF9, does not display typical F-actin depolymerizing activity. Instead, ADF9 effectively stabilizes actin filaments in vitro and concomitantly bundles actin filaments with the highest efficiency under acidic conditions. Competition experiments show that ADF9 antagonizes ADF1 activity by reducing its ability to potentiate F-actin depolymerization. Accordingly, ectopic expression of ADF1 and ADF9 in tobacco cells has opposite effects. ADF1 severs actin filaments/bundles and promotes actin cytoskeleton disassembly, whereas ADF9 induces the formation of long bundles. Together these data reveal an additional degree of complexity in the comprehension of the biological functions of the ADF family and illustrate that antagonist activities can be displayed by seemingly equivalent actin-binding proteins.
authors.affiliation: Centre de Recherche Public-Santé, Luxembourg, Luxembourg.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Tholl
authors.forename: Flora
authors.initials: F
authors.lastname: Moreau
authors.forename: Céline
authors.initials: C
authors.lastname: Hoffmann
authors.forename: Karthik
authors.initials: K
authors.lastname: Arumugam
authors.forename: Monika
authors.initials: M
authors.lastname: Dieterle
authors.forename: Danièle
authors.initials: D
authors.lastname: Moes
authors.forename: Katrin
authors.initials: K
authors.lastname: Neumann
authors.forename: André
authors.initials: A
authors.lastname: Steinmetz
authors.forename: Clément
authors.initials: C
authors.lastname: Thomas
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D051339:Actin Depolymerizing Factors / Q000037:antagonists & inhibitors* / Q000502:physiology; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins; D003599:Cytoskeleton / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics
chemical_list: D051339:Actin Depolymerizing Factors; D029681:Arabidopsis Proteins