title: Profilin regulates F-actin network homeostasis by favoring formin over Arp2/3 complex.
abstract: Fission yeast cells use Arp2/3 complex and formin to assemble diverse filamentous actin (F-actin) networks within a common cytoplasm for endocytosis, division, and polarization. Although these homeostatic F-actin networks are usually investigated separately, competition for a limited pool of actin monomers (G-actin) helps to regulate their size and density. However, the mechanism by which G-actin is correctly distributed between rival F-actin networks is not clear. Using a combination of cell biological approaches and in vitro reconstitution of competition between actin assembly factors, we found that the small G-actin binding protein profilin directly inhibits Arp2/3 complex-mediated actin assembly. Profilin is therefore required for formin to compete effectively with excess Arp2/3 complex for limited G-actin and to assemble F-actin for contractile ring formation in dividing cells.
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Cristian
authors.initials: C
authors.lastname: Suarez
authors.affiliation: Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Carroll
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Burke
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Jenna R
authors.initials: JR
authors.lastname: Christensen
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bestul
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Sees
authors.affiliation: Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: James
authors.affiliation: Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA. Electronic address: sirotkiv@upstate.edu.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Sirotkin
authors.affiliation: Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA. Electronic address: drkovar@uchicago.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Kovar
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D051304:Profilins / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D051304:Profilins; D029702:Schizosaccharomyces pombe Proteins