title: Dictyostelium differentiation-inducing factor-3 activates glycogen synthase kinase-3beta and degrades cyclin D1 in mammalian cells.
abstract: In search of chemical substances applicable for the treatment of cancer and other proliferative disorders, we studied the signal transduction of Dictyostelium differentiation-inducing factors (DIFs) in mammalian cells mainly using HeLa cells. Although DIF-1 and DIF-3 both strongly inhibited cell proliferation by inducing G(0)/G(1) arrest, DIF-3 was more effective than DIF-1. DIF-3 suppressed cyclin D1 expression at both mRNA and protein levels, whereas the overexpression of cyclin D1 overrode DIF-3-induced cell cycle arrest. The DIF-3-induced decrease in the amount of cyclin D1 protein preceded the reduction in the level of cyclin D1 mRNA. The decrease in cyclin D1 protein seemed to be caused by accelerated proteolysis, since it was abrogated by N-acetyl-Leu-Leu-norleucinal, a proteasome inhibitor. DIF-3-induced degradation of cyclin D1 was also prevented by treatment with lithium chloride, an inhibitor of glycogen synthase kinase-3beta (GSK-3beta), suggesting that DIF-3 induced cyclin D1 proteolysis through the activation of GSK-3beta. Indeed, DIF-3 dephosphorylated Ser(9) and phosphorylated tyrosine on GSK-3beta, and it stimulated GSK-3beta activity in an in vitro kinase assay. Moreover, DIF-3 was revealed to induce the nuclear translocation of GSK-3beta by immunofluorescent microscopy and immunoblotting of subcellular protein fractions. These results suggested that DIF-3 activates GSK-3beta to accelerate the proteolysis of cyclin D1 and that this mechanism is involved in the DIF-3-induced G(0)/G(1) arrest in mammalian cells.
authors.affiliation: Department of Clinical Pharmacology, Graduate School of Medical Sciences, Graduate School of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan. yanaga@clipharm.med.kyushu-u.ac.jp
authors.forename: Fumi
authors.initials: F
authors.lastname: Takahashi-Yanaga
authors.forename: Yoji
authors.initials: Y
authors.lastname: Taba
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Miwa
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kubohara
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Masato
authors.initials: M
authors.lastname: Hirata
authors.forename: Sachio
authors.initials: S
authors.lastname: Morimoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sasaguri
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000378:metabolism*; D056742:Cyclin D2; D056743:Cyclin D3; D016213:Cyclins / Q000378:metabolism; D003546:Cysteine Endopeptidases; D004023:Dictyostelium / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004730:Endothelium, Vascular / Q000166:cytology; D016193:G1 Phase; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006367:HeLa Cells; D006588:Hexanones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D018021:Lithium Chloride / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016192:Resting Phase, Cell Cycle; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014471:Umbilical Veins / Q000166:cytology
chemical_list: C080336:CCND2 protein, human; C534696:CCND3 protein, human; D056742:Cyclin D2; D056743:Cyclin D3; D016213:Cyclins; D006588:Hexanones; D007976:Leupeptins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; C063261:acetylleucyl-leucyl-norleucinal; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; C055364:1-(3-chloro-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; D019938:Cyclin D1; D012313:RNA; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D018021:Lithium Chloride