Institute of Human Genetics, Ruprecht-Karls-Universitaet Heidelberg, Im Neuenheimer Feld 328, Heidelberg 69120, Germany.
EMBO Rep. 2012 Feb 1;13(2):129-34. doi: 10.1038/embor.2011.240.
Xenopus paraxial protocadherin (PAPC) regulates cadherin-mediated cell adhesion and promotes the planar cell polarity (PCP) pathway. Here we report that PAPC functions in the Xenopus gastrula as an inhibitor of the Wnt/β-catenin pathway. The intracellular domain of PAPC interacts with casein kinase 2 beta (CK2β), which is part of the CK2 holoenzyme. The CK2α/β complex stimulates Wnt/β-catenin signalling, and the physical interaction of CK2β with PAPC antagonizes this activity. By this mechanism, PAPC restricts the expression of Wnt target genes during gastrulation. These experiments identify a novel function of protocadherins as regulators of the Wnt pathway.
非洲爪蟾轴旁原钙黏蛋白（PAPC）调节钙黏蛋白介导的细胞黏附，并促进平面细胞极性（PCP）途径。在这里，我们报告 PAPC 在非洲爪蟾原肠胚中作为 Wnt/β-连环蛋白途径的抑制剂发挥作用。PAPC 的细胞内域与酪蛋白激酶 2β（CK2β）相互作用，CK2β 是 CK2 全酶的一部分。CK2α/β 复合物刺激 Wnt/β-连环蛋白信号转导，而 CK2β 与 PAPC 的物理相互作用拮抗这种活性。通过这种机制，PAPC 在原肠胚形成过程中限制 Wnt 靶基因的表达。这些实验确定了原钙黏蛋白作为 Wnt 途径调节剂的新功能。
