Engineering a single ubiquitin ligase for the selective degradation of all activated ErbB receptor tyrosine kinases.

Interrogating specific cellular activities often entails the dissection of posttranslational modifications or functional redundancy conferred by protein families, which demands more sophisticated research tools than simply eliminating a specific gene product by gene targeting or RNAi. We have developed a novel methodology that involves engineering a single SCFβTrCP-based ubiquitin ligase that is capable of not only simultaneously targeting the entire family of ErbB receptor tyrosine kinases for ubiquitination and degradation, but also selectively recruiting only activated ErbBs. The engineered SCFβTrCP ubiquitin ligase effectively blocked ErbB signaling and attenuated oncogenicity in breast cancer cells, yet had little effect on the survival and growth of non-cancerous breast epithelial cells. Therefore, engineering ubiquitin ligases offers a simple research tool to dissect the specific traits of tumorigenic protein families, and provides a rapid and feasible means to expand the dimensionality of drug discovery by assessing protein families or posttranslational modifications as potential drug targets.

探究特定的细胞活动往往需要剖析蛋白质家族所赋予的翻译后修饰或功能冗余，这需要比通过基因打靶或RNA干扰简单地消除特定基因产物更为复杂的研究工具。我们开发了一种新的方法，该方法涉及构建一种基于SCFβTrCP的单一泛素连接酶，它不仅能够同时靶向ErbB受体酪氨酸激酶的整个家族进行泛素化和降解，还能选择性地仅招募活化的ErbB。这种构建的SCFβTrCP泛素连接酶有效地阻断了乳腺癌细胞中的ErbB信号传导并减弱了其致癌性，但对非癌性乳腺上皮细胞的存活和生长几乎没有影响。因此，构建泛素连接酶为剖析致癌蛋白质家族的特定特性提供了一种简单的研究工具，并通过将蛋白质家族或翻译后修饰评估为潜在的药物靶点，为拓展药物发现的维度提供了一种快速可行的手段。