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Purified Wnt 5a protein activates or inhibits

Purified Wnt 5a protein activates or inhibits β -catenin-TCF signaling depending on receptor context. Mikels et al., 2006, PLOS Biology. Wnts antagonize Wnts. Mouse limb bud. Over-expression of Wnt 5 blocks the ability of Wnt 8 to promote dorsal cell fate in Xenopus.

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Purified Wnt 5a protein activates or inhibits

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  1. PurifiedWnt 5a protein activates or inhibits β-catenin-TCF signaling depending on receptor context Mikels et al., 2006, PLOS Biology

  2. Wnts antagonize Wnts Mouse limb bud Over-expression of Wnt 5 blocks the ability of Wnt 8 to promote dorsal cell fate in Xenopus. - Torres et al., 2003, J. Cell Biol. In the distal tip of mouse limb buds, Wnt 5a antagonizes b-catenin signaling, since in Wnt 5a -/- limbs higher levels of b-catenin can be detected in the distal tip. - Topol et al., 2003, J. Cell Biol. Removal of maternal and zygotic functions of zebrafish Wnt 5 result in variable degrees of dorsalization, including formation of secondary axis. - Westfall et al., 2003, Dev. Biol.

  3. How to inhibit the canonical signaling…? Dominant negative Wnt 11 and CaMK II promotes dorsal cell fates. - Kuhl et al., 2000, J. Biol. Chem. Over-expression of Wnt 5 can activate Nemo-like kinase, which in C. elegans and mammalian cells Inhibit Tcf transcription factors to which b-catenin binds to regulate gene expression. - Ishitani et al., 2003, Mol. Cell. Biol. Siah 2 (b-catenin destruction complex) is transcriptionally activated by Wnt 5a. - Topol et al., 2003, J. Cell Biol.

  4. Purified Wnt 5a protein inhibits canonical Wnt signaling SuperTopflash in 293 cells wnt 3a  wnt 5a (after 1, 3hr) wnt 5a  6hr after washing  wnt 3a

  5. Wnt 5a does not affect b-catenin protein stabilization Cytosolic fraction of 293 cells 293 cells Wnt 5a protein competes with Wnt 3a for Fz receptor context. Siah 2, which targets b-catenin for b-TrCP independent proteasomal degradation, is transcriptionally activated by Wnt 5a. - Topol et al., 2003, J. Cell Biol.

  6. G-protein wnt 5a Ca ++ CaMKII TAK/NLK mitogen activated Signaling cascade b-cat TCF/LEF - phosphorylation DNA Wnt 5a - mediated inhibition of canonical signaling is not associated with Wnt- stimulated Ca++ flux * PTX (pertussis toxin) : inhibition of G protein binding with membrane receptor * LPA (lysophosphatidic acid) : agonist of G protein signaling Wnt stimulated calcium flux * Ionomycin :raises the intracellular level of Ca2+

  7. Wnt 5a protein activates b-catenin signaling depending on receptor context XWnt 5a RNA with Xfz4 RNA leads to the synergistic activation of Wnt/b-cat target genes in Xenopus animal caps. - Umbhauer et al., 2000, EMBO J

  8. An alternative Wnt receptor, mRor2, mediates Wnt 5a’s inhibitory activity

  9. Expression of mRor2 is required for Wnt 5a- mediated inhibition of canonical Wnt signaling SuperTopflash LRP cotransfection

  10. 293 Membrane tethered form (no transmembrane & cytoplasmic domain) Transmembrane domain : O Cytoplasmic domain : X

  11. A member of the Fz protein family (hFz5) mediating axis induction by Wnt 5a. - He et al., 1997, Scinece.

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