title: Plant formin AtFH5 is an evolutionarily conserved actin nucleator involved in cytokinesis.
abstract: Formins are actin-organizing proteins that are involved in cytokinesis and cell polarity. In the plant Arabidopsis thaliana, there are more than 20 formin homologues, all of which have unknown roles. In this study, we characterize specific cellular and molecular functions of the Arabidopsis formin AtFH5. Despite the low identity of AtFH5 to yeast and mammalian formins, the AtFH5 protein interacts with the barbed end of actin filaments and nucleates actin-filament polymerization in vitro, as is the case in yeast and mammals. In vivo, the AtFH5-GFP fusion protein localizes to the cell plate, a plant-specific membranous component that is assembled at the plane of cell division. Consistent with these data, loss of function of atfh5 compromises cytokinesis in the seed endosperm. Furthermore, endogenous AtFH5 transcripts accumulate in the posterior pole of the endosperm and loss of function of atfh5 perturbs proper morphogenesis of the endosperm posterior pole. Although cytokinesis in animals, yeast and plants occurs through morphologically distinct mechanisms, our study finds that formin recruitment to sites of actin assembly is a common feature of cell division among eukaryotes.
authors.affiliation: EMBO YIP team, Unité Mixte de Recherche 5667, Institut Fédératif de Recherche 128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, F-69364 Lyon cedex 07, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Ingouff
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Fitz Gerald
authors.forename: Christophe
authors.initials: C
authors.lastname: Guérin
authors.forename: Hélène
authors.initials: H
authors.lastname: Robert
authors.forename: Mikael Blom
authors.initials: MB
authors.lastname: Sørensen
authors.forename: Daniel
authors.initials: D
authors.lastname: Van Damme
authors.forename: Danny
authors.initials: D
authors.lastname: Geelen
authors.forename: Laurent
authors.initials: L
authors.lastname: Blanchoin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Berger
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D048749:Cytokinesis / Q000502:physiology*; D005091:Exons; D049452:Green Fluorescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D000199:Actins; D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C500405:FH5 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins