title: Actin-Based Transport Adapts Polarity Domain Size to Local Cellular Curvature.
abstract: Intracellular structures and organelles such as the nucleus, the centrosome, or the mitotic spindle typically scale their size to cell size [1]. Similarly, cortical polarity domains built around the active form of conserved Rho-GTPases, such as Cdc42p, exhibit widths that may range over two orders of magnitudes in cells with different sizes and shapes [2-6]. The establishment of such domains typically involves positive feedback loops based on reaction-diffusion and/or actin-mediated vesicle transport [3, 7, 8]. How these elements may adapt polarity domain size to cellular geometry is not known. Here, by tracking the width of successive oscillating Cdc42-GTP domains in fission yeast spores [9], we find that domain width scales with local cell-surface radii of curvature over an 8-fold range, independently of absolute cell volume, surface, or Cdc42-GTP concentration. This local scaling requires formin-nucleated cortical actin cables and the fusion of secretory vesicles transported along these cables with the membrane. These data suggest that reaction-diffusion may set a minimal domain size and that secretory vesicle transport along actin cables may dilute and extend polarity domains to adapt their size to local cell-surface curvature. This work reveals that actin networks may act as micrometric curvature sensors and uncovers a generic morphogenetic principle for how polarity domains define their size according to cell morphologies.
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Daria
authors.initials: D
authors.lastname: Bonazzi
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Armin
authors.initials: A
authors.lastname: Haupt
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tanimoto
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Delacour
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France; Université Pierre et Marie Curie, 15 Rue de l'Ecole de Médecine, 75205 Paris Cedex 06, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Salort
authors.affiliation: Institut Jacques Monod, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France. Electronic address: nicolas.minc@ijm.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Minc
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism; D013172:Spores, Fungal / Q000166:cytology / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000235:genetics* / Q000378:metabolism
chemical_list: D000199:Actins; D029702:Schizosaccharomyces pombe Proteins; D020764:cdc42 GTP-Binding Protein