In vivo activation and nuclear translocation of phosphorylated glycogen synthase kinase-3beta in neuronal apoptosis: links to tau phosphorylation

Eur J Neurosci. 2002 Feb;15(4):651-60. doi: 10.1046/j.1460-9568.2002.01899.x.

Abstract

The roles of glycogen synthase kinase-3beta (GSK-3beta) and tau phosphorylation were examined in seven-day-old rats injected with the NMDA receptor antagonist (MK801) that is known to induce neuronal apoptosis. Immunoblot and immunohistochemical analysis of brain samples demonstrated a site-specific increase in tau phosphorylation associated with the relocalization of the protein to the nuclear/perinuclear region of apoptotic neurons. In addition, a tau 32-kDa fragment was detected, suggesting that tau was a target of intracellular proteolysis in MK801-treated brains. The proteolytically modified form of tau has reduced ability to bind to microtubules. GSK-3beta kinase assay and immunoblottings of active (tyrosine-216) and inactive (serine-9) forms of GSK-3beta revealed a rapid and transient increase in the kinase activity. Lithium chloride, a GSK-3beta inhibitor, prevented tau phosphorylation suggesting that tau phosphorylation is mediated by the activation of GSK-3beta. Confocal microscopy using double labelling of tau and GSK-3beta revealed that the activation of GSK-3beta in neurons was associated with early (2 h) nuclear translocation of tyrosine-216 GSK-3beta. The execution phase of neuronal apoptosis was accompanied by a selective phosphorylation of serine-9 and dephosphorylation of tyrosine-216 GSK-3beta. These findings demonstrate that in vivo, GSK-3beta kinase activation and nuclear translocation are early stress signals of neuronal apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Active Transport, Cell Nucleus / physiology*
  • Animals
  • Animals, Newborn
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Brain / cytology
  • Brain / enzymology*
  • Brain / growth & development*
  • Calcium-Calmodulin-Dependent Protein Kinases / drug effects
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Cell Compartmentation / drug effects
  • Cell Compartmentation / physiology
  • Cell Nucleus / drug effects
  • Cell Nucleus / enzymology
  • Cell Nucleus / ultrastructure
  • Cytoplasm / drug effects
  • Cytoplasm / enzymology
  • Cytoplasm / ultrastructure
  • Cytoskeleton / drug effects
  • Cytoskeleton / metabolism
  • Excitatory Amino Acid Antagonists / pharmacology
  • Female
  • Glycogen Synthase Kinase 3
  • Glycogen Synthase Kinases
  • Male
  • Nerve Degeneration / chemically induced
  • Nerve Degeneration / metabolism
  • Nerve Degeneration / physiopathology
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / enzymology*
  • Peptide Fragments / drug effects
  • Peptide Fragments / metabolism
  • Phosphorylation / drug effects
  • Rats
  • Rats, Wistar
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Receptors, N-Methyl-D-Aspartate / metabolism
  • Stress, Physiological / chemically induced
  • Stress, Physiological / enzymology
  • Stress, Physiological / physiopathology
  • tau Proteins / drug effects
  • tau Proteins / metabolism*

Substances

  • Excitatory Amino Acid Antagonists
  • Peptide Fragments
  • Receptors, N-Methyl-D-Aspartate
  • tau Proteins
  • Glycogen Synthase Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Glycogen Synthase Kinase 3