title: Single-molecule analysis of chemotactic signaling in Dictyostelium cells.
abstract: Single-molecule imaging techniques were used to reveal the binding of individual cyclic adenosine 3',5'-monophosphate molecules to heterotrimeric guanine nucleotide-binding protein coupled receptors on the surface of living Dictyostelium discoideum cells. The binding sites were uniformly distributed and diffused rapidly in the plane of the membrane. The probabilities of individual association and dissociation events were greater for receptors at the anterior end of the cell. Agonist-induced receptor phosphorylation had little effect on any of the monitored properties, whereas G protein coupling influenced the binding kinetics. These observations illustrate the dynamic properties of receptors involved in gradient sensing and suggest that these may be polarized in chemotactic cells.
authors.affiliation: Recognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Corporation (JST)., Osaka 562-0035, Japan. ueda@phys1.med.osaka-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Ueda
authors.forename: Y
authors.initials: Y
authors.lastname: Sako
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: P
authors.initials: P
authors.lastname: Devreotes
authors.forename: T
authors.initials: T
authors.lastname: Yanagida
mesh_terms: D000818:Animals; D002232:Carbocyanines / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002633:Chemotaxis; D000242:Cyclic AMP / Q000378:metabolism*; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004058:Diffusion; D006153:Guanosine Diphosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008856:Microscopy, Fluorescence; D009154:Mutation; D010766:Phosphorylation; D011554:Pseudopodia / Q000378:metabolism; D011953:Receptors, Cyclic AMP / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D002232:Carbocyanines; D011953:Receptors, Cyclic AMP; C089187:cyanine dye 3; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D000242:Cyclic AMP; D020962:Heterotrimeric GTP-Binding Proteins