An actin nucleation mechanism mediated by Bni1 and profilin.
Formins are required for cell polarization and cytokinesis, but do not have a defined biochemical activity. In Saccharomyces cerevisiae, formins and the actin-monomer-binding protein profilin are specifically required to assemble linear actin structures called 'actin cables'. These structures seem to be assembled independently of the Arp2/3 complex, the only well characterized cellular mediator of actin nucleation. Here, an activated yeast formin was purified and found to promote the nucleation of actin filaments in vitro. Formin-dependent actin nucleation was stimulated by profilin. Thus, formin and profilin mediate actin nucleation by an Arp2/3-independent mechanism. These findings suggest that distinct actin nucleation mechanisms may underlie the assembly of different actin cytoskeletal structures.
Department of Pediatric Oncology, The Dana-Farber Cancer Institute Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA.
Isabelle
I
Sagot
Avital A
AA
Rodal
James
J
Moseley
Bruce L
BL
Goode
David
D
Pellman
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001704:Biopolymers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D003599:Cytoskeleton / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins; D051304:Profilins; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
C102245:ARP3 protein, S cerevisiae; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D001704:Biopolymers; C105191:Bni1 protein, S cerevisiae; C086662:CDC3 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D008840:Microfilament Proteins; D051304:Profilins; D029701:Saccharomyces cerevisiae Proteins