A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling
A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling
复制标题
DOI：
10.1073/pnas.1418651112
复制
发表时间：
2015-03-24
影响因子：
11.1
通讯作者：
Grant, Barth D.
中科院分区：
文献类型：
--
作者：
Bai, Zhiyong;Grant, Barth D.
许多关键膜蛋白和脂质（包括信号受体、小分子转运蛋白和粘附蛋白）的功能都需要内体到高尔基体的转运。逆转录酶复合体因其在早期内体的货物分选和囊泡出芽中的作用而闻名，在大多数情况下导致货物与跨高尔基体网络（TGN）融合。从回收内体到 TGN 的转运也有报道，但对介导这一转运步骤的分子了解甚少。在这里，我们提供的证据表明，F-BAR 结构域蛋白 TOCA-1 和 TOCA-2（Cdc42 依赖性肌动蛋白组装转导子）、小 GTPase CDC-42（细胞分裂控制蛋白 42）、相关极性蛋白 PAR-6（分区缺陷 6）和 PKC-3/非典型蛋白激酶 C，以及 WAVE 肌动蛋白成核复合物介导 MIG-14/Wls 和 TGN-38/TGN38 货物蛋白从回收内体到秀丽隐杆线虫的 TGN。我们的结果表明，CDC-42、TOCA 蛋白和 WAVE 成分 WVE-1 在肠道中的 RME-1 阳性回收内体上富集，与作用于早期内体的逆转录体成分不同。此外，我们发现逆行货物TGN-38在SNX-3（逆转录体成分）耗尽后被困在早期内体中，但在CDC-42耗尽后主要被困在回收内体中，表明CDC-42相关复合物在逆转录体后在不同的细胞器中发挥作用。因此，我们鉴定了一组介导逆行再循环的相互作用蛋白质，并将这些蛋白质与一个鲜为人知的运输步骤联系起来，即再循环内体到高尔基体的运输。我们还提供了该通路在 WNT 信号传导中的生理重要性的证据。
Endosome-to-Golgi transport is required for the function of many key membrane proteins and lipids, including signaling receptors, small-molecule transporters, and adhesion proteins. The retromer complex is well-known for its role in cargo sorting and vesicle budding from early endosomes, in most cases leading to cargo fusion with the trans-Golgi network (TGN). Transport from recycling endosomes to the TGN has also been reported, but much less is understood about the molecules that mediate this transport step. Here we provide evidence that the F-BAR domain proteins TOCA-1 and TOCA-2 (Transducer of Cdc42 dependent actin assembly), the small GTPase CDC-42 (Cell division control protein 42), associated polarity proteins PAR-6 (Partitioning defective 6) and PKC-3/atypical protein kinase C, and the WAVE actin nucleation complex mediate the transport of MIG-14/Wls and TGN-38/TGN38 cargo proteins from the recycling endosome to the TGN in Caenorhabditis elegans. Our results indicate that CDC-42, the TOCA proteins, and the WAVE component WVE-1 are enriched on RME-1-positive recycling endosomes in the intestine, unlike retromer components that act on early endosomes. Furthermore, we find that retrograde cargo TGN-38 is trapped in early endosomes after depletion of SNX-3 (a retromer component) but is mainly trapped in recycling endosomes after depletion of CDC-42, indicating that the CDC-42-associated complex functions after retromer in a distinct organelle. Thus, we identify a group of interacting proteins that mediate retrograde recycling, and link these proteins to a poorly understood trafficking step, recycling endosome-to-Golgi transport. We also provide evidence for the physiological importance of this pathway in WNT signaling.