title: Autonomous and nonautonomous regulation of axis formation by antagonistic signaling via 7-span cAMP receptors and GSK3 in Dictyostelium.
abstract: Early during Dictyostelium development a fundamental cell-fate decision establishes the anteroposterior (prestalk/prespore) axis. Signaling via the 7-transmembrane cAMP receptor CAR4 is essential for creating and maintaining a normal pattern; car4-null alleles have decreased levels of prestalk-specific mRNAs but enhanced expression of prespore genes. car4- cells produce all of the signals required for prestalk differentiation but lack an extracellular factor necessary for prespore differentiation of wild-type cells. This secreted factor decreases the sensitivity of prespore cells to inhibition by the prestalk morphogen DIF-1. At the cell autonomous level, CAR4 is linked to intracellular circuits that activate prestalk but inhibit prespore differentiation. The autonomous action of CAR4 is antagonistic to the positive intracellular signals mediated by another cAMP receptor, CAR1 and/or CAR3. Additional data indicate that these CAR-mediated pathways converge at the serine/threonine protein kinase GSK3, suggesting that the anterior (prestalk)/posterior (prespore) axis of Dictyostelium is regulated by an ancient mechanism that is shared by the Wnt/Fz circuits for dorsoventral patterning during early Xenopus development and establishing Drosophila segment polarity.
authors.affiliation: Laboratory of Cellular and Developmental Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-2715, USA.
authors.forename: G T
authors.initials: GT
authors.lastname: Ginsburg
authors.forename: A R
authors.initials: AR
authors.lastname: Kimmel
mesh_terms: D000818:Animals; D029742:Caenorhabditis elegans Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D015342:DNA Probes / Q000235:genetics / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics* / Q000254:growth & development; D004330:Drosophila / Q000235:genetics / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D038362:Glycogen Synthase Kinase 3; D015801:Helminth Proteins / Q000378:metabolism; D006588:Hexanones; D006843:Hydrocarbons, Chlorinated; D009154:Mutation; D011506:Proteins; D015800:Protozoan Proteins; D011953:Receptors, Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013170:Spores; D014981:Xenopus / Q000235:genetics / Q000254:growth & development
chemical_list: C090317:CAR4 protein, Dictyostelium discoideum; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D015342:DNA Probes; C490570:Differentiation-inducing factor-1, Dictyostelium; D015801:Helminth Proteins; D006588:Hexanones; D006843:Hydrocarbons, Chlorinated; D011506:Proteins; D015800:Protozoan Proteins; D011953:Receptors, Cyclic AMP; D011994:Recombinant Proteins; D000242:Cyclic AMP; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3