title: A specific DIF binding protein in Dictyostelium.
abstract: Differentiation Inducing Factor (DIF-1), a small chlorinated organic molecule which is produced during Dictyostelium development, is believed to be the morphogen that controls the stalk-specific pathway of differentiation. We describe the identification and characterization of a protease-sensitive activity from cell lysates which binds tritiated DIF-1 with the properties expected of a DIF receptor. Scatchard and linear subtraction plots show a single class of binding sites, of high affinity (Kd = 1.8 nM) and low abundance (1100 sites/cell). The activity elutes from heparin-agarose as a single peak. Various DIF-1 analogues compete for binding in proportion to their activities in a stalk cell differentiation bioassay. The amount of binding activity is developmentally regulated, peaking shortly before the appearance of the prestalk-prespore pattern and before the developmental rise in DIF concentration; the rise occurs at the same time that prestalk-specific genes become DIF inducible. Addition of cyclic AMP to aggregated cells, which induces post-aggregative gene expression in general, also induces the binding activity.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: R
authors.initials: R
authors.lastname: Insall
authors.forename: R R
authors.initials: RR
authors.lastname: Kay
mesh_terms: D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D000242:Cyclic AMP / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004023:Dictyostelium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D006588:Hexanones / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics
chemical_list: D002352:Carrier Proteins; D006588:Hexanones; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; D000242:Cyclic AMP