Functional dissection of the N-terminal extracellular domains of Frizzled 6 reveals their roles for receptor localization and Dishevelled recruitment
Functional dissection of the N-terminal extracellular domains of Frizzled 6 reveals their roles for receptor localization and Dishevelled recruitment
复制标题
DOI：
10.1074/jbc.ra118.004763
复制
发表时间：
2018-11-16
影响因子：
4.8
通讯作者：
Schulte, Gunnar
中科院分区：
文献类型：
--
作者：
Valnohova, Jana;Kowalski-Jahn, Maria;Schulte, Gunnar
Frizzled（FZD）蛋白属于G蛋白偶联受体（GPCR）的F类，并且对于涉及wingless/int-1（WNT）家族的分泌脂糖蛋白的各种途径是必需的。FZD中的WNT结合富半胱氨酸结构域（CRD）位于N末端，并通过在不同FZD同系物中具有可变长度的接头结构域连接至七个跨膜结构域的受体核心。然而，这个连接域的功能和重要性知之甚少。在这里，我们使用FZD的系统诱变（6）来定义足以用于受体表面表达和细胞内支架蛋白Dishevelled（DVL）的募集的最小N末端结构域。此外，我们在FZD接头结构域中鉴定了进化上保守的半胱氨酸三联体，其对于受体膜表达和DVL的募集至关重要。我们的研究结果是一致的概念，保守的半胱氨酸在连接域的FZD协助形成一个共同的二级结构在这个地区。我们提出，这种结构可能参与激动剂结合和受体激活机制，类似于其他GPCR已知的结合和激活机制。
The Frizzled (FZD) proteins belong to class F of G protein-coupled receptors (GPCRs) and are essential for various pathways involving the secreted lipoglycoproteins of the wingless/int-1 (WNT) family. A WNT-binding cysteine-rich domain (CRD) in FZDs is N-terminally located and connected to the seven transmembrane domain-spanning receptor core by a linker domain that has a variable length in different FZD homologs. However, the function and importance of this linker domain are poorly understood. Here we used systematic mutagenesis of FZD(6) to define the minimal N-terminal domain sufficient for receptor surface expression and recruitment of the intracellular scaffold protein Dishevelled (DVL). Further, we identified a triad of evolutionarily conserved cysteines in the FZD linker domain that is crucial for receptor membrane expression and recruitment of DVL. Our results are in agreement with the concept that the conserved cysteines in the linker domain of FZDs assist with the formation of a common secondary structure in this region. We propose that this structure could be involved in agonist binding and receptor activation mechanisms that are similar to the binding and activation mechanisms known for other GPCRs.