Divalent interaction of the GGAs with the Rabaptin-5-Rabex-5 complex
Divalent interaction of the GGAs with the Rabaptin-5-Rabex-5 complex
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DOI：
10.1093/emboj/cdg015
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发表时间：
2003-01-02
期刊：
影响因子：
11.4
通讯作者：
Bonifacino, JS
中科院分区：
文献类型：
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作者：
Mattera, R;Arighi, CN;Bonifacino, JS
从跨高尔基网络(TGN)衍生的运输载体到内体的货物转移涉及一系列仍未确定的系留/融合事件。在这里，我们分析可能在这一过程中发挥作用的分子相互作用。我们证明了GGAs是一个依赖Arf的网状蛋白适配器家族，参与了TGN货物的选择，并与Rabaptin-5-Rabex-5复合体相互作用，Rabaptin-5-Rabex-5复合体是一种Rab4/Rab5效应器，调节内体融合。这些相互作用是两部分的：GGA-GAE结构域识别Rabaptin-5预测的随机卷曲中的FGPLV序列(残基439-443)(该序列也被Gamma1和Gamma2适配的耳朵识别)，而GGA-GAT结构域与Rabaptin-5的C端卷曲结合。GGA-Rabaptin-5的相互作用减少了笼蛋白与GGA-铰链结构域的结合，绿色荧光蛋白(GFP)-Rabaptin-5的表达将内源性GGA1及其相关货物的定位转移到了扩大的早期内小体。因此，这些观察确定了GAE/伽马适应耳区的结合序列，并揭示了调节TGN货物输出的蛋白质与内体拴系/融合事件之间的功能联系。
Cargo transfer from trans-Golgi network (TGN)-derived transport carriers to endosomes involves a still undefined set of tethering/fusion events. Here we analyze a molecular interaction that may play a role in this process. We demonstrate that the GGAs, a family of Arf-dependent clathrin adaptors involved in selection of TGN cargo, interact with the Rabaptin-5-Rabex-5 complex, a Rab4/Rab5 effector regulating endosome fusion. These interactions are bipartite: GGA-GAE domains recognize an FGPLV sequence (residues 439-443) in a predicted random coil of Rabaptin-5 (a sequence also recognized by the gamma1-and gamma2-adaptin ears), while GGA-GAT domains bind to the C-terminal coiled-coils of Rabaptin-5. The GGA-Rabaptin-5 interaction decreases binding of clathrin to the GGA-hinge domain, and expression of green fluorescent protein (GFP)-Rabaptin-5 shifts the localization of endogenous GGA1 and associated cargo to enlarged early endosomes. These observations thus identify a binding sequence for GAE/gamma-adaptin ear domains and reveal a functional link between proteins regulating TGN cargo export and endosomal tethering/fusion events.