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The specificity of membrane traffic involves tethers at destination organelles that selectively capture incoming transport vesicles to allow SNAREs on opposing membranes to then assemble and drive fusion. Tethers include both protein complexes and long coiled-coil proteins, although how they contribute to specificity remains unclear. The golgin coiled-coil proteins at the Golgi apparatus capture vesicles from different origins, but the vesicle-specific molecular cues that they recognize are unknown. Vesicle tethering is typically a transient process and therefore is challenging to interrogate in vivo. Thus, we have used a system in which an ectopic golgin causes vesicles to accumulate in a tethered state. By applying proximity biotinylation to the golgin-captured vesicles, we identify TBC1D23, an apparently catalytically inactive member of a family of Rab GTPase-activating proteins (GAPs), as a vesicle-golgin adaptor that is required for endosome-to-Golgi trafficking. The Rab GAP domain of TBC1D23 binds to a conserved motif at the tip of golgin-245 and golgin-97 at the trans-Golgi, while the C terminus binds to the WASH complex on endosome-derived vesicles. Thus, TBC1D23 is a specificity determinant that links the vesicle to the target membrane during endosome-to-Golgi trafficking.

In the version of Supplementary Table 1 originally published with this Article, in the sheet relating to Fig. 3c, all values in the ‘golgin-97-mito’ column were 1.3 times larger than the actual values, which was due to author error when generating the Supplementary Table. These errors did not affect the graph in Fig. 3c, which was plotted with the correct values. Supplementary Table 1 has now been replaced so that it contains the correct values.