Synthetic TGN liposomes were prepared using a mixture of lipids that approximates the lipid composition of the TGN (Klemm et al., 2009 (link)). Lipids were combined, vacuum dried, rehydrated in HK buffer (20 mM Hepes, pH 7.4, and 150 mM KOAc), and extruded through 100-nm filters (Whatman) to generate liposomes. See Table S3 for the composition of TGN and phosphatidylcholine liposomes.