title: Receptor-dependent and tyrosine phosphatase-mediated inhibition of GSK3 regulates cell fate choice.
abstract: Asymmetric body axis formation is central to metazoan development. Dictyostelium establishes an anterior/posterior axis utilizing seven-transmembrane cAMP morphogen receptors (CARs) and GSK3-mediated signal transductions that has a parallel with metazoan Wnt/Frizzled-GSK3 pathways. In Dictyostelium, GSK3 promotes posterior cell patterning but inhibits anterior cell differentiation. Tyrosine kinase ZAK1 mediates GSK3 activation. We now show that CAR4 regulates a tyrosine phosphatase that inhibits GSK3 activity. We have also identified essential phosphotyrosines in GSK3, confirmed their role in activated/deactivated regulation and cell fate decisions, and relate them to the predicted 3D structure of GSK3beta. CARs differentially regulate GSK3 activity by selectively activating a tyrosine phosphatase or kinase for pattern formation. The findings may provide a comparative understanding of CAR-GSK3 and Wnt/Frizzled-GSK3 pathways.
authors.affiliation: Laboratory of Cellular and Developmental Biology, Building 50/3351, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Leung
authors.initials: L
authors.lastname: Kim
authors.forename: Adrian
authors.initials: A
authors.lastname: Harwood
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kimmel
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004023:Dictyostelium / Q000254:growth & development*; D004789:Enzyme Activation; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D011953:Receptors, Cyclic AMP / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D011953:Receptors, Cyclic AMP; D038362:Glycogen Synthase Kinase 3