A divergent canonical WNT-signaling pathway regulates microtubule dynamics: dishevelled signals locally to stabilize microtubules

J Cell Biol. 2004 Jan 19;164(2):243-53. doi: 10.1083/jcb.200309096.

Abstract

Dishevelled (DVL) is associated with axonal microtubules and regulates microtubule stability through the inhibition of the serine/threonine kinase, glycogen synthase kinase 3beta (GSK-3beta). In the canonical WNT pathway, the negative regulator Axin forms a complex with beta-catenin and GSK-3beta, resulting in beta-catenin degradation. Inhibition of GSK-3beta by DVL increases beta-catenin stability and TCF transcriptional activation. Here, we show that Axin associates with microtubules and unexpectedly stabilizes microtubules through DVL. In turn, DVL stabilizes microtubules by inhibiting GSK-3beta through a transcription- and beta-catenin-independent pathway. More importantly, axonal microtubules are stabilized after DVL localizes to axons. Increased microtubule stability is correlated with a decrease in GSK-3beta-mediated phosphorylation of MAP-1B. We propose a model in which Axin, through DVL, stabilizes microtubules by inhibiting a pool of GSK-3beta, resulting in local changes in the phosphorylation of cellular targets. Our data indicate a bifurcation in the so-called canonical WNT-signaling pathway to regulate microtubule stability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Animals, Newborn
  • COS Cells
  • Cell Line
  • Cerebellum / cytology
  • Chlorocebus aethiops
  • Dishevelled Proteins
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Mice
  • Microtubules / physiology*
  • Microtubules / ultrastructure
  • Neurons / cytology
  • Neurons / physiology*
  • Phosphoproteins / physiology*
  • Protein-Tyrosine Kinases / physiology
  • Proto-Oncogene Proteins / physiology*
  • Signal Transduction
  • Transfection
  • Wnt Proteins

Substances

  • Adaptor Proteins, Signal Transducing
  • Dishevelled Proteins
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • Wnt Proteins
  • Protein-Tyrosine Kinases
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, mouse
  • Glycogen Synthase Kinase 3