The WDR11 complex facilitates the tethering of AP-1-derived vesicles

Vesicluar transport of proteins from endosomes to the trans-Golgi network (TGN) is an essential cellular pathway, but much of its machinery is still unknown. A screen for genes involved in endosome-to-TGN trafficking produced two hits, the adaptor protein-1 (AP-1 complex), which facilitates vesicle budding, and WDR11. Here we demonstrate that WDR11 forms a stable complex with two other proteins, which localises to the TGN region and does not appear to be associated with AP-1, suggesting it may act downstream from budding. In a vesicle tethering assay, capture of vesicles by golgin-245 was substantially reduced in WDR11-knockout cells. Moreover, structured illumination microscopy and relocation assays indicate that the WDR11 complex is initially recruited onto vesicles rather than the TGN, where it may in turn recruit the golgin binding partner TBC1D23. We propose that the complex acts together with TBC1D23 to facilitate the golgin-mediated capture of vesicles that were generated using AP-1.