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XB-ART-6728
Mol Cell Biol September 1, 2002; 22 (17): 6100-10.

Regulation of Wnt/LRP signaling by distinct domains of Dickkopf proteins.

Brott BK , Sokol SY .


Abstract
Dickkopfs (Dkks) are secreted developmental regulators composed of two cysteine-rich domains. We report that the effects of Dkks depend on molecular context. Although Wnt8 signaling is inhibited by both Dkk1 and Dkk2 in Xenopus embryos, the same pathway is activated upon interaction of Dkk2 with the Wnt coreceptor LRP6. Analysis of individual Dkk domains and chimeric Dkks shows that the carboxy-terminal domains of both Dkks associate with LRP6 and are necessary and sufficient for Wnt8 inhibition, whereas the amino-terminal domain of Dkk1 plays an inhibitory role in Dkk-LRP interactions. Our study illustrates how an inhibitor of a pathway may be converted into an activator and is the first study to suggest a molecular mechanism for how a ligand other than Wnt can positively regulate beta-catenin signaling.

PubMed ID: 12167704
PMC ID: PMC133995
Article link: Mol Cell Biol


Species referenced: Xenopus
Genes referenced: dkk1 dkk2 lrp1 lrp6 ptpra rpsa wnt8a

References [+] :
Aravind, A colipase fold in the carboxy-terminal domain of the Wnt antagonists--the Dickkopfs. 1998, Pubmed, Xenbase