Selective activation of Wnt signaling pathway using with purified Wnt proteins

Wnt是聚糖和脂质修饰的形态发生素，对细胞反应很重要，但Wnt如何在极化上皮细胞中分泌仍不清楚。在这里，我们表明Wnts的顶基分泌是由不同的机制调节。Wnt 11和Wnt 3a分别在极化上皮细胞的顶部和基底部分泌。Wntless定位于基底外侧膜。 质谱分析显示，Wnt 11被复合/杂合型（Asn 40）、高甘露糖型（Asn 90）和高甘露糖/杂合型（Asn 300）聚糖修饰，Wnt 3a被两种高甘露糖型聚糖（Asn 87和Asn 298）修饰。Wnt 11的顶端分泌需要Asn 40和半乳糖凝集素-3的糖基化处理，而Wnt 3a的基底侧分泌需要网格蛋白和衔接蛋白-1。这些结果表明，Wls在Wnt 11和Wnt 3a的极化分泌中具有不同的作用，Wnt 11和Wnt 3a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