E-cadherin phosphorylation occurs during its biosynthesis to promote its cell surface stability and adhesion.
E-cadherin phosphorylation occurs during its biosynthesis to promote its cell surface stability and adhesion.
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DOI：
10.1091/mbc.e14-01-0690
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发表时间：
2014-08-15
影响因子：
3.3
通讯作者：
Gottardi CJ
中科院分区：
文献类型：
--
作者：
McEwen AE;Maher MT;Mo R;Gottardi CJ
钙粘附素-连环蛋白复合体在粘连连接处介导细胞与细胞的黏附。E-钙粘附素在其β-连环蛋白结合区的磷酸化促进了E-钙粘附素的表面稳定性和强大的细胞间黏附。E-钙粘附素在其β-连环蛋白结合区高度磷酸化，这种磷酸化在体外增加了它与β-连环蛋白的亲和力。然而，大多数钙粘附素磷酸化的关键丝氨酸的鉴定以及这些丝氨酸修饰的粘附性后果仍然未知。在这项研究中，我们发现E-钙粘附素的β-连环蛋白结合域中只有三个丝氨酸负责大多数放射性磷酸盐的掺入。这些丝氨酸是与β-连环蛋白结合以及E-钙粘蛋白和β-连环蛋白相互稳定所必需的。表达缺乏磷的E-钙粘附素(3S>；A)的细胞由于内吞作用增强和通过溶酶体室降解而表现出最小的细胞间黏附。相反，这些丝氨酸上的负电荷替代(3S和GT；D)对抗钙粘附素的内吞作用，并恢复野生型的黏附水平。钙粘蛋白激酶位于细胞膜的近端，在钙粘蛋白到达细胞表面之前对其进行修饰。综上所述，这些数据表明，E-钙粘蛋白的磷酸化在很大程度上是钙粘素-连环蛋白复合体形成、表面稳定性和功能所必需的。
The cadherin–catenin complex mediates cell–cell adhesion at adherens junctions. Phosphorylation of E-cadherin in its β-catenin–binding domain promotes surface stability of E-cadherin and robust cell–cell adhesion. E-cadherin is highly phosphorylated within its β-catenin–binding region, and this phosphorylation increases its affinity for β-catenin in vitro. However, the identification of key serines responsible for most cadherin phosphorylation and the adhesive consequences of modification at such serines have remained unknown. In this study, we show that as few as three serines in the β-catenin–binding domain of E-cadherin are responsible for most radioactive phosphate incorporation. These serines are required for binding to β-catenin and the mutual stability of both E-cadherin and β-catenin. Cells expressing a phosphodeficient (3S>A) E-cadherin exhibit minimal cell–cell adhesion due to enhanced endocytosis and degradation through a lysosomal compartment. Conversely, negative charge substitution at these serines (3S>D) antagonizes cadherin endocytosis and restores wild-type levels of adhesion. The cadherin kinase is membrane proximal and modifies the cadherin before it reaches the cell surface. Together these data suggest that E-cadherin phosphorylation is largely constitutive and integral to cadherin–catenin complex formation, surface stability, and function.