Selective activation of Wnt signaling pathway using with purified Wnt proteins

WNT是糖类和脂类修饰的形态前体，对细胞反应很重要，但WNT是如何在极化的上皮细胞中分泌的仍不清楚。在这里，我们展示了WNTS的根基分泌受到不同机制的调节。在极化的上皮细胞中，WNT11和WNT3a分别在顶端和基底部分泌。Wnless定位于基底外侧膜。质谱学分析表明，Wnt11被复合/杂化(Asn40)、高甘露糖(Asn90)和高甘露糖/杂化(Asn300)型多糖修饰，Wnt3a被两种高甘露糖型(Asn87和Asn298)修饰。Wnt11的顶端分泌需要Asn40和Galectin-3的糖基化处理，而Wnt3a的基侧分泌需要网状蛋白和适配器蛋白-1。这些结果表明，WLS对WNT11和WNT3a的极化分泌具有不同的作用，WNTs的糖基化过程决定了它们的分泌途径

Wnts are glycan- and lipid-modified morphogens that are important for cellular responses, but how Wnt is secreted in polarized epithelial cells remains unclear. Here we show the apicobasal secretion of Wnts is regulated by different mechanisms. Wnt11 and Wnt3a were secreted apically and basolaterally, respectively, in polarized epithelial cells. Wntless was localized to the basolateral membrane. Mass-spectrometric analyses revealed that Wnt11 is modified with complex/hybrid-(Asn40), high-mannose-(Asn90), and high-mannose/hybrid-(Asn300) type glycans and that Wnt3a is modified with two high-mannose-type glycans (Asn87 and Asn298). Glycosylation processing at Asn40 and galectin-3 were required for the apical secretion of Wnt11, while clathrin and adaptor protein-1 were required for the basolateral secretion of Wnt3a. These results suggest that Wls has different roles on the polarized secretion of Wnt11 and Wnt3a and that glycosylation processing of Wnts decides their secretory routes