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The structural basis of DKK-mediated inhibition of Wnt/LRP signaling

Ju Bao1, Jie J Zheng, Dianqing Wu

  • 1Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.

Science Signaling
|May 17, 2012
PubMed

Insights

Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6) are key to Wnt signaling. New structural insights reveal how Dickkopf proteins inhibit this pathway by binding LRP5/6.

Area of Science:

  • Molecular biology
  • Biochemistry
  • Structural biology

Background:

  • Low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6) are crucial co-receptors for canonical Wnt-β-catenin signaling.
  • Wnt proteins bind to Frizzled receptors, initiating downstream signaling cascades.
  • Dickkopf (DKK)-related proteins are known inhibitors of the Wnt pathway, antagonizing LRP5/6 function.

Purpose of the Study:

  • To elucidate the molecular mechanism by which Dickkopf (DKK)-related proteins inhibit Wnt signaling.
  • To understand the structural basis of the interaction between LRP5/6 and DKK proteins.

Main Methods:

  • X-ray crystallography to determine the structure of the LRP6 ectodomain in complex with DKK1.
  • Mutagenesis studies to investigate the functional consequences of specific interactions.

Main Results:

  • Crystal structures revealed the precise binding interface between the LRP6 ectodomain and DKK1.
  • Mutagenesis data confirmed the importance of specific residues in mediating DKK-LRP6 interaction and Wnt signaling inhibition.

Conclusions:

  • The findings provide significant molecular insights into DKK-mediated antagonism of Wnt signaling.
  • This structural and functional understanding of LRP5/6 and DKK interaction is vital for targeting Wnt pathway dysregulation.

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