Further evidence that the tyrosine phosphorylation of glycogen synthase kinase-3 (GSK3) in mammalian cells is an autophosphorylation event

Adam Cole, Sheelagh Frame, Philip Cohen (Lead / Corresponding author)

    Research output: Contribution to journalArticle

    232 Citations (Scopus)

    Abstract

    Phosphorylation of the endogenous GSK3α (glycogen synthase kinase-3α) at Tyr279 and GSK3β at Tyr216 was suppressed in HEK-293 or SH-SY5Y cells by incubation with pharmacological inhibitors of GSK3, but not by an Src-family inhibitor, 4-amino-5-(4- chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), or a general protein tyrosine kinase inhibitor (genistein). GSK3β transfected into HEK-293 cells or Escherichia coli became phosphorylated at Tyr216, but catalytically inactive mutants did not. GSK3β expressed in insect Sf21 cells or E. coli was extensively phosphorylated at Tyr216, but the few molecules lacking phosphate at this position could autophosphorylate at Tyr216 in vitro after incubation with MgATP. The rate of autophosphorylation was unaffected by dilution and was suppressed by the GSK3 inhibitor kenpaullone. Wild-type GSK3β was unable to catalyse the tyrosine phosphorylation of catalytically inactive GSK3β lacking phosphate at Tyr216. Our results indicate that the tyrosine phosphorylation of GSK3 is an intramolecular autophosphorylation event in the cells that we have studied and that this modification enhances the stability of the enzyme.

    Original languageEnglish
    Pages (from-to)249-255
    Number of pages7
    JournalBiochemical Journal
    Volume377
    Issue number1
    DOIs
    Publication statusPublished - 1 Jan 2004

    Keywords

    • Glycogen synthase kinase-3 (GSK3)
    • Indirubin
    • Kenpaullone
    • Phosphotyrosine
    • Tyrosine kinase

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