title: Temporal and spatial regulation of chemotaxis.
abstract: The ability to sense and respond to shallow gradients of extracellular signals is remarkably similar in Dictyostelium discoideum amoebae and mammalian leukocytes. Chemoattractant receptors and G proteins are fairly evenly distributed along the cell surface. Receptor occupancy generates local excitatory and global inhibitory processes that balance to control the chemotactic response. Uniform stimuli transiently recruit PI3Ks to, and release PTEN from, the plasma membrane, while gradients of chemoattractant cause the two enzymes to bind to the membrane at the front and back of the cell, respectively. Interference with PI3Ks alters chemotaxis, and disruption of PTEN broadens PI localization and actin polymerization in parallel. Thus, counteracting signals from the upstream elements of the pathway converge to regulate the key enzymes of PI metabolism, localize these lipids, and direct pseudopod formation.
authors.affiliation: Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Miho
authors.initials: M
authors.lastname: Iijima
authors.forename: Yi Elaine
authors.initials: YE
authors.lastname: Huang
authors.forename: Peter
authors.initials: P
authors.lastname: Devreotes
mesh_terms: D000818:Animals; D016764:Cell Polarity; D002633:Chemotaxis / Q000502:physiology*; D004023:Dictyostelium; D019204:GTP-Binding Proteins / Q000502:physiology; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010744:Phosphoric Monoester Hydrolases / Q000502:physiology; D011956:Receptors, Cell Surface / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000502:physiology
chemical_list: D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D019869:Phosphatidylinositol 3-Kinases; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; D019204:GTP-Binding Proteins