THE KLHL12-CULLIN-3 UBIQUITIN LIGASE NEGATIVELY REGULATES THE WNT-BETA-CATENIN

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定是研究者机构。Dishevelled是一种保守的蛋白质，解释Frizzled受体接收的信号。使用串联亲和纯化策略和质谱法，我们已经鉴定了与Dishevelled相关的蛋白质，包括含有Broad Complex的Cullin-3泛素连接酶复合物、Tramtrack和Bric a Brac（BTB）蛋白Kelch样12（KLHL 12）。这种E3泛素连接酶复合物以Wnt依赖的方式被募集到Dishevelled，从而促进其多聚泛素化和降解。功能分析表明，这种泛素连接酶调控Dishevelled拮抗Wnt-β-连环蛋白途径在培养细胞，以及在非洲爪蟾和斑马鱼胚胎。考虑到不同的基于Cullin-1的SCF（β-TrCP）复合物调节β-连环蛋白稳定性的证据，我们关于Dishevelled稳定性的数据表明，两种不同的泛素连接酶复合物调节Wnt-β-连环蛋白途径。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dishevelled is a conserved protein that interprets signals received by Frizzled receptors. Using a tandem-affinity purification strategy and mass spectrometry we have identified proteins associated with Dishevelled, including a Cullin-3 ubiquitin ligase complex containing the Broad Complex, Tramtrack and Bric a Brac (BTB) protein Kelch-like 12 (KLHL12). This E3 ubiquitin ligase complex is recruited to Dishevelled in a Wnt-dependent manner that promotes its poly-ubiquitination and degradation. Functional analyses demonstrate that regulation of Dishevelled by this ubiquitin ligase antagonizes the Wnt-beta-catenin pathway in cultured cells, as well as in Xenopus and zebrafish embryos. Considered with evidence that the distinct Cullin-1 based SCF(beta-TrCP)complex regulates beta-catenin stability, our data on the stability of Dishevelled demonstrates that two distinct ubiquitin ligase complexes regulate the Wnt-beta-catenin pathway.