title: The cyclin-dependent kinase inhibitor roscovitine inhibits kinase activity, cell proliferation, multicellular development, and Cdk5 nuclear translocation in Dictyostelium discoideum.
abstract: Roscovitine, a cyclin-dependent kinase (Cdk) inhibitor, inhibited kinase activity and the axenic growth of Dictyostelium discoideum at micromolar concentrations. Growth was almost fully rescued in 50 µM and ≈ 50% rescued in 100 µM roscovitine-treated cultures by the over-expression of Cdk5-GFP. This supports the importance of Cdk5 function during cell proliferation in Dictyostelium and indicates that Cdk5 is a primary target of the drug. Roscovitine did not affect the expression of Cdk5 protein during axenic growth but did inhibit its nuclear translocation. This novel result suggests that the effects of roscovitine could be due in part to altering Cdk5 translocation in other systems as well. Kinase activity was inhibited by roscovitine in assays using AX3 whole cell lysates, but not in assays using lysates from Cdk5-GFP over-expressing cells. At higher concentrations, roscovitine impaired slug and fruiting body formation. Fruiting bodies that did form were small and produced relatively fewer spores many of which were round. However, roscovitine did not affect stalk cell differentiation. Together with previous findings, these data reveal that roscovitine inhibits Cdk5 during growth and as yet undefined Cdks during mid-late development.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Huber
authors.forename: Danton H
authors.initials: DH
authors.lastname: O'Day
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D002467:Cell Nucleus / Q000201:enzymology; D049109:Cell Proliferation / Q000187:drug effects; D051360:Cyclin-Dependent Kinase 5 / Q000032:analysis / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004023:Dictyostelium / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology*; D012100:Reproduction, Asexual; D000077546:Roscovitine
chemical_list: D047428:Protein Kinase Inhibitors; D011687:Purines; D000077546:Roscovitine; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases