Insulin controls glucose uptake into muscle and fat cells by inducing a net redistribution of GLUT4 from intracellular storage to the plasma membrane (PM). The TBC1D4-RAB10 signaling module is required for insulin-stimulated GLUT4 translocation to the PM, although where it intersects GLUT4 traffic was unknown. Here we demonstrate that TBC1D4-RAB10 functions to control GLUT4 mobilization from a Trans Golgi Network (TGN) storage compartment, establishing that insulin, in addition to regulating the PM proximal effects of GLUT4-containing vesicles docking to and fusion with the PM, also directly regulates the behavior of GLUT4 deeper within the cell. We also show that GLUT4 is retained in an element/domain of the TGN from which newly synthesized lysosomal proteins are targeted to the late endosomes and the ATP7A copper transporter is translocated to the PM by elevated copper. Insulin does not mobilize ATP7A nor does copper mobilize GLUT4, and RAB10 is not required for copper-elicited ATP7A mobilization. Consequently, GLUT4 intracellular sequestration and mobilization by insulin is achieved, in part, through utilizing a region of the TGN devoted to specialized cargo transport in general rather than being specific for GLUT4. Our results define the GLUT4-containing region of the TGN as a sorting and storage site from which different cargo are mobilized by distinct signals through unique molecular machinery.

胰岛素通过诱导 GLUT4 从细胞内储存到质膜 (PM) 的净重新分配来控制肌肉和脂肪细胞中的葡萄糖摄取。TBC1D4-RAB10 信号模块是胰岛素刺激的 GLUT4 易位到 PM 所必需的，尽管它与 GLUT4 流量相交的位置尚不清楚。在这里，我们证明 TBC1D4-RAB10 的功能是控制 GLUT4 从跨高尔基体网络 (TGN) 储存室的动员，确定胰岛素除了调节含有 GLUT4 的囊泡与 PM 对接和融合的 PM 近端效应之外，还直接调节细胞内 GLUT4 的行为。我们还表明，GLUT4 保留在 TGN 的元件/结构域中，新合成的溶酶体蛋白从该元件/结构域靶向晚期内体，并且 ATP7A 铜转运蛋白通过升高的铜易位至 PM。胰岛素不会动员 ATP7A，铜也不会动员 GLUT4，并且铜引发的 ATP7A 动员不需要 RAB10。因此，胰岛素对 GLUT4 的细胞内隔离和动员部分是通过利用 TGN 中专门用于一般货物运输的区域而不是专门针对 GLUT4 的区域来实现的。我们的结果将 TGN 的含有 GLUT4 的区域定义为一个分类和存储位点，通过独特的分子机制通过不同的信号从该位点调动不同的货物。