title: Rotational movement of the formin mDia1 along the double helical strand of an actin filament.
abstract: Formin homology proteins (formins) elongate actin filaments (F-actin) by continuously associating with filament tips, potentially harnessing actin-generated pushing forces. During this processive elongation, formins are predicted to rotate along the axis of the double helical F-actin structure (referred to here as helical rotation), although this has not yet been definitively shown. We demonstrated helical rotation of the formin mDia1 by single-molecule fluorescence polarization (FL(P)). FL(P) of labeled F-actin, both elongating and depolymerizing from immobilized mDia1, oscillated with a periodicity corresponding to that of the F-actin long-pitch helix, and this was not altered by actin-bound nucleotides or the actin-binding protein profilin. Thus, helical rotation is an intrinsic property of formins. To harness pushing forces from growing F-actin, formins must be anchored flexibly to cell structures.
authors.affiliation: Laboratory of Single-Molecule Cell Biology, Tohoku University Graduate School of Life Sciences, 6-3 Aoba, Aramaki-Aza, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mizuno
authors.forename: Chiharu
authors.initials: C
authors.lastname: Higashida
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Yuan
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Ishizaki
authors.forename: Shuh
authors.initials: S
authors.lastname: Narumiya
authors.forename: Naoki
authors.initials: N
authors.lastname: Watanabe
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D005454:Fluorescence Polarization; D000080865:Formins; D051379:Mice; D008954:Models, Biological; D051304:Profilins / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012399:Rotation
chemical_list: D000199:Actins; D002352:Carrier Proteins; C491464:Diap1 protein, mouse; D000080865:Formins; D051304:Profilins; D011993:Recombinant Fusion Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate