Recycling pathways determine the kinetic signatures and localizations of transmembrane Golgi proteins. (A) Model of Golgi recycling pathways and corresponding kinetic signatures. Straight horizontal arrows represent time during the life cycle of a cisterna, other arrows represent traffic pathways, rounded rectangles represent Golgi cisternae of different ages, and colored ovals represent transmembrane proteins. Based on evidence presented here and elsewhere, we suggest that there are three sequential intra-Golgi recycling pathways. The first pathway is designated COPI(b) to distinguish it from COPI(a)-mediated Golgi-to-ER recycling, which is not depicted. This COPI(b) pathway generates early kinetic signatures (green). The second pathway is designated AP-1/Ent5(a), and it recycles proteins such as Sys1 to generate intermediate kinetic signatures (magenta). The third pathway is designated AP-1/Ent5(b), and it recycles TGN proteins such as Drs2 to generate late kinetic signatures (blue). In addition, a pathway of GGA-dependent transport to PVE compartments followed by recycling to nascent TGN cisternae generates separate kinetic signatures (orange). For a given transmembrane Golgi protein, the kinetic signature governs localization to cisternae in a particular age range. Some Golgi proteins might follow more than one pathway, in which case their kinetic signatures would be combinations of the ones depicted here. (B) Quantification of kinetic signatures for Golgi transmembrane proteins that are believed to follow four distinct recycling pathways. The colors match those in A. Shown are average and SEM values for arrival and departure times relative to Drs2, based on the same data that were used to generate plots in other figures. Negative numbers indicate arrival or departure earlier than Drs2. The average signal duration for Drs2 was 68.8 ± 1.2 s based on a total of 157 traces, with nearly all of the events in the range of 40–90 s.