title: Spatial control of actin polymerization during neutrophil chemotaxis.
abstract: Neutrophils respond to chemotactic stimuli by increasing the nucleation and polymerization of actin filaments, but the location and regulation of these processes are not well understood. Here, using a permeabilized-cell assay, we show that chemotactic stimuli cause neutrophils to organize many discrete sites of actin polymerization, the distribution of which is biased by external chemotactic gradients. Furthermore, the Arp2/3 complex, which can nucleate actin polymerization, dynamically redistributes to the region of living neutrophils that receives maximal chemotactic stimulation, and the least-extractable pool of the Arp2/3 complex co-localizes with sites of actin polymerization. Our observations indicate that chemoattractant-stimulated neutrophils may establish discrete foci of actin polymerization that are similar to those generated at the posterior surface of the intracellular bacterium Listeria monocytogenes. We propose that asymmetrical establishment and/or maintenance of sites of actin polymerization produces directional migration of neutrophils in response to chemotactic gradients.
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0554, USA.
authors.forename: O D
authors.initials: OD
authors.lastname: Weiner
authors.forename: G
authors.initials: G
authors.lastname: Servant
authors.forename: M D
authors.initials: MD
authors.lastname: Welch
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchison
authors.forename: J W
authors.initials: JW
authors.lastname: Sedat
authors.forename: H R
authors.initials: HR
authors.lastname: Bourne
mesh_terms: D051377:Actin-Related Protein 2; D000199:Actins / Q000097:blood* / Q000737:chemistry / Q000648:ultrastructure; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002463:Cell Membrane Permeability; D016764:Cell Polarity; D002634:Chemotaxis, Leukocyte; D003598:Cytoskeletal Proteins; D006801:Humans; D008089:Listeria monocytogenes / Q000502:physiology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D015398:Signal Transduction
chemical_list: C495926:ACTR2 protein, human; D051377:Actin-Related Protein 2; D000199:Actins; D003598:Cytoskeletal Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine