FIGURE 4:

Evolution of the ARF family and its regulators. (A) The timing of the emergence of the relevant protein subfamilies is shown mapped on a simplified tree of eukaryotes. The polygons, circles, and squares denote the latest point by which the ARF GTPases, GAPs, and GEFs must have evolved, respectively, with the names of the subfamilies given to the right. The names of the eukaryotic supergroups are in italics, while the relevant “reconstructed ancestor” discussed in the text are in bold and noted by a dashed line. (B) Overlay of ARF1-5 evolution with that of the nine ARF GAP subfamilies that possess multiple paralogues. ARF evolution is depicted in black and Arf GAP in gray, with duplications at the base of Holozoa and Vertebrata. Relevant evolutionary transitions are illustrated by dashed lines.