title: Patch coalescence as a mechanism for eukaryotic directional sensing.
abstract: Eukaryotic cells possess a sensible chemical compass allowing them to orient toward sources of soluble chemicals. The extracellular chemical signal triggers separation of the cell membrane into two domains populated by different phospholipid molecules and oriented along the signal anisotropy. We propose a theory of this polarization process, which is articulated into subsequent stages of germ nucleation, patch coarsening, and merging into a single domain. We find that the polarization time, t{epsilon}, depends on the anisotropy degree through the power law t{epsilon} infinity epsilon{-2}, and that in a cell of radius R there should exist a threshold value epsilon{th} infinity R{-1} for the smallest detectable anisotropy.
authors.affiliation: Politecnico di Torino and CNISM, Corso Duca degli Abruzzi 24, 10121 Torino, Italy and INFN, via Pietro Giuria 1, 10125 Torino, Italy. andrea.gamba@polito.it
authors.forename: A
authors.initials: A
authors.lastname: Gamba
authors.forename: I
authors.initials: I
authors.lastname: Kolokolov
authors.forename: V
authors.initials: V
authors.lastname: Lebedev
authors.forename: G
authors.initials: G
authors.lastname: Ortenzi
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D002450:Cell Communication / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D004058:Diffusion; D005057:Eukaryotic Cells / Q000502:physiology*; D007700:Kinetics; D015233:Models, Statistical; D051059:PTEN Phosphohydrolase / Q000737:chemistry / Q000502:physiology; D013816:Thermodynamics
chemical_list: D051059:PTEN Phosphohydrolase