title: Combinatorial cell-specific regulation of GSK3 directs cell differentiation and polarity in Dictyostelium.
abstract: In Dictyostelium, the interaction of secreted cAMP with specific cell surface receptors regulates the activation/de-activation of GSK3, which mediates developmental cell patterning. In addition, Dictyostelium cells polarize in response to extracellular cAMP, although a potential role for GSK3 in this pathway has not been investigated. Previously, we had shown that ZAK1 was an activating tyrosine kinase for GSK3 function in Dictyostelium and we now identify ZAK2 as the other tyrosine kinase in the cAMP-activation pathway for GSK3; no additional family members exist. We also now show that tyrosine phosphorylation/activation of GSK3 by ZAK2 and ZAK1 separately regulate GSK3 in distinct differentiated cell populations, and that ZAK2 acts in both autonomous and non-autonomous pathways to regulate these cell-type differentiations. Finally, we demonstrate that efficient polarization of Dictyostelium towards cAMP depends on ZAK1-mediated tyrosine phosphorylation of GSK3. Combinatorial regulation of GSK3 by ZAK kinases in Dictyostelium guides cell polarity, directional cell migration and cell differentiation, pathways that extend the complexity of GSK3 signaling throughout the development of Dictyostelium.
authors.affiliation: Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Leung
authors.initials: L
authors.lastname: Kim
authors.forename: Joseph
authors.initials: J
authors.lastname: Brzostowski
authors.forename: Amit
authors.initials: A
authors.lastname: Majithia
authors.forename: Nam-Sihk
authors.initials: NS
authors.lastname: Lee
authors.forename: Vanessa
authors.initials: V
authors.lastname: McMains
authors.forename: Alan R
authors.initials: AR
authors.lastname: Kimmel
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D016764:Cell Polarity / Q000187:drug effects / Q000235:genetics*; D002633:Chemotaxis / Q000187:drug effects / Q000235:genetics; D000242:Cyclic AMP / Q000494:pharmacology; D004023:Dictyostelium / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D038362:Glycogen Synthase Kinase 3