Formins direct Arp2/3-independent actin filament assembly to polarize cell growth in yeast.
Formins have been implicated in the regulation of cytoskeletal structure in animals and fungi. Here we show that the formins Bni1 and Bnr1 of budding yeast stimulate the assembly of actin filaments that function as precursors to tropomyosin-stabilized cables that direct polarized cell growth. With loss of formin function, cables disassemble, whereas increased formin activity causes the hyperaccumulation of cable-like filaments. Unlike the assembly of cortical actin patches, cable assembly requires profilin but not the Arp2/3 complex. Thus formins control a distinct pathway for assembling actin filaments that organize the overall polarity of the cell.
Evangelista
Marie
M
Department of Biology, Queen's University, Kingston, Ontario, Canada.
Pruyne
David
D
Amberg
David C
DC
Boone
Charles
C
Bretscher
Aanthony
A
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000235:genetics* / Q000648:ultrastructure; D002352:Carrier Proteins / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics*; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000235:genetics / Q000648:ultrastructure; D004705:Endocytosis; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D008840:Microfilament Proteins; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D014335:Tropomyosin
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; C106463:BNR1 protein, S cerevisiae; C105191:Bni1 protein, S cerevisiae; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D008840:Microfilament Proteins; D029701:Saccharomyces cerevisiae Proteins; D014335:Tropomyosin