Development and Disease Group, Max Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany.
FASEB J. 2010 Jul;24(7):2417-26. doi: 10.1096/fj.09-150615. Epub 2010 Mar 9.
Dishevelled (Dvl) is a multifunctional effector of different Wnt cascades. Both canonical Wnt3a and noncanonical Wnt5a stimulate casein-kinase-1 (CK1) -mediated phosphorylation of Dvl, visualized as electrophoretic mobility shift [phosphorylated and shifted Dvl (ps-Dvl)]. However, the role of this phosphorylation remains obscure. Here we report the functional interaction of ps-Dvl with the receptor tyrosine kinase Ror2, which is an alternative Wnt receptor and is able to inhibit canonical Wnt signaling. We demonstrate interaction between Ror2 and ps-Dvl at the cell membrane after Wnt3a or Wnt5a stimulus dependent on CK1. Ps-Dvl interacts with the C-terminal proline-serine-threonine-rich domain of Ror2, which is required for efficient inhibition of canonical Wnt signaling. We further show that the Dvl C terminus, which seems to be exposed in ps-Dvl and efficiently binds Ror2, is an intrinsic negative regulator of the canonical Wnt pathway downstream of beta-catenin. The Dvl C terminus is necessary and sufficient to inhibit canonical Wnt/beta-catenin signaling, which is dependent on the presence of Ror2. Furthermore, both the Dvl C terminus and CK1epsilon can inhibit the Wnt5a/Ror2/ATF2 pathway in mammalian cells and Xenopus explant cultures. This suggests that phosphorylation of Dvl triggers negative feedback regulation for different branches of Wnt signaling in a Ror2-dependent manner.
Dishevelled (Dvl) 是不同 Wnt 级联的多功能效应物。经典的 Wnt3a 和非经典的 Wnt5a 都能刺激 Dvl 的 CK1-介导的磷酸化，表现为电泳迁移率的改变（磷酸化和迁移的 Dvl [ps-Dvl]）。然而，这种磷酸化的作用仍然不清楚。在这里，我们报告了 ps-Dvl 与受体酪氨酸激酶 Ror2 的功能相互作用，Ror2 是一种替代的 Wnt 受体，能够抑制经典的 Wnt 信号。我们证明了在 Wnt3a 或 Wnt5a 刺激后，ps-Dvl 在细胞膜上与 CK1 依赖性的 Ror2 相互作用。ps-Dvl 与 Ror2 的 C 端脯氨酸-丝氨酸-苏氨酸富含结构域相互作用，这是有效抑制经典 Wnt 信号所必需的。我们进一步表明，Dvl 的 C 端，似乎在 ps-Dvl 中暴露并能有效地与 Ror2 结合，是 beta-catenin 下游经典 Wnt 途径的内在负调节剂。Dvl 的 C 端是抑制经典 Wnt/beta-catenin 信号所必需和充分的，这依赖于 Ror2 的存在。此外，Dvl 的 C 端和 CK1epsilon 都能在哺乳动物细胞和 Xenopus 外植体培养物中抑制 Wnt5a/Ror2/ATF2 途径。这表明 Dvl 的磷酸化以依赖于 Ror2 的方式触发不同分支的 Wnt 信号的负反馈调节。
