title: Role of formins in actin assembly: nucleation and barbed-end association.
abstract: Nucleation of branched actin filaments by the Arp2/3 complex is a conserved process in eukaryotic cells, yet the source of unbranched actin filaments has remained obscure. In yeast, formins stimulate assembly of actin cables independently of Arp2/3. Here, the conserved core of formin homology domains 1 and 2 of Bni1p (Bni1pFH1FH2) was found to nucleate unbranched actin filaments in vitro. Bni1pFH2 provided the minimal region sufficient for nucleation. Unique among actin nucleators, Bni1pFH1FH2 remained associated with the growing barbed ends of filaments. This combination of properties suggests a direct role for formins in regulating nucleation and polarization of unbranched filamentous actin structures.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: David
authors.initials: D
authors.lastname: Pruyne
authors.forename: Marie
authors.initials: M
authors.lastname: Evangelista
authors.forename: Changsong
authors.initials: C
authors.lastname: Yang
authors.forename: Erfei
authors.initials: E
authors.lastname: Bi
authors.forename: Sally
authors.initials: S
authors.lastname: Zigmond
authors.forename: Anthony
authors.initials: A
authors.lastname: Bretscher
authors.forename: Charles
authors.initials: C
authors.lastname: Boone
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism*; D003571:Cytochalasin B / Q000494:pharmacology; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D008840:Microfilament Proteins; D008854:Microscopy, Electron; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D000199:Actins; C105191:Bni1 protein, S cerevisiae; D005656:Fungal Proteins; D008840:Microfilament Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D003571:Cytochalasin B