Wnt3a and Dkk1 Regulate Distinct Internalization Pathways of LRP6 to Tune the Activation of β-Catenin Signaling

Hideki Yamamoto, Hiroshi Sakane, Hideki Yamamoto, Tatsuo Michiue, Akira Kikuchi

Research output: Contribution to journalArticlepeer-review

176 Citations (Scopus)

Abstract

Wnt and Dickkopf (Dkk) regulate the stabilization of β-catenin antagonistically in the Wnt signaling pathway; however, the molecular mechanism is not clear. In this study, we found that Wnt3a acts in parallel to induce the caveolin-dependent internalization of low-density-lipoprotein receptor-related protein 6 (LRP6), as well as the phosphorylation of LRP6 and the recruitment of Axin to LRP6 on the cell surface membrane. The phosphorylation and internalization of LRP6 occurred independently of one another, and both were necessary for the accumulation of β-catenin. In contrast, Dkk1, which inhibits Wnt3a-dependent stabilization of β-catenin, induced the internalization of LRP6 with clathrin. Knockdown of clathrin suppressed the Dkk1-dependent inhibition of the Wnt3a response. Furthermore, Dkk1 reduced the distribution of LRP6 in the lipid raft fraction where caveolin is associated. These results indicate that Wnt3a and Dkk1 shunt LRP6 to distinct internalization pathways in order to activate and inhibit the β-catenin signaling, respectively.

Original languageEnglish
Pages (from-to)37-48
Number of pages12
JournalDevelopmental Cell
Volume15
Issue number1
DOIs
Publication statusPublished - Jul 8 2008
Externally publishedYes

Keywords

  • CELLBIO
  • SIGNALING

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Developmental Biology
  • Cell Biology

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