Wingless inactivates glycogen synthase kinase-3 via an intracellular signalling pathway which involves a protein kinase C.
The Drosophila gene product Wingless (Wg) is a secreted glycoprotein and a member of the Wnt gene family. Genetic analysis of Drosophila epidermal development has defined a putative paracrine Wg signalling pathway involving the zeste-white 3/shaggy (zw3/sgg) gene product. Although putative components of Wg- (and by inference Wnt-) mediated signalling pathways have been identified by genetic analysis, the biochemical significance of most factors remains unproven. Here we show that in mouse 10T1/2 fibroblasts the activity of glycogen synthase kinase-3 (GSK-3), the murine homologue of Zw3/Sgg, is inactivated by Wg. This occurs through a signalling pathway that is distinct from insulin-mediated regulation of GSK-3 in that Wg signalling to GSK-3 is insensitive to wortmannin. Additionally, Wg-induced inactivation of GSK-3 is sensitive to both the protein kinase C (PKC) inhibitor Ro31-8220 and prolonged pre-treatment of 10T1/2 fibroblasts with phorbol ester. These findings provide the first biochemical evidence in support of the genetically defined pathway from Wg to Zw3/Sgg, and suggest a previously uncharacterized role for a PKC upstream of GSK-3/Zw3 during Wnt/Wg signal transduction.
Developmental Biology Team, Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, UK.
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D
Cook
M J
MJ
Fry
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K
Hughes
R
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Sumathipala
J R
JR
Woodgett
T C
TC
Dale
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D017077:Culture Media, Conditioned; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D051379:Mice; D011090:Polyenes / Q000494:pharmacology; D011494:Protein Kinases / Q000819:agonists / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015398:Signal Transduction; D020123:Sirolimus; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D051155:Wnt1 Protein; D000077191:Wortmannin
D000730:Androstadienes; D017077:Culture Media, Conditioned; D029721:Drosophila Proteins; D004791:Enzyme Inhibitors; D011090:Polyenes; D011518:Proto-Oncogene Proteins; D051155:Wnt1 Protein; C074622:wg protein, Drosophila; D011494:Protein Kinases; D038341:Glycogen Synthase Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D013755:Tetradecanoylphorbol Acetate; D020123:Sirolimus; D000077191:Wortmannin