Overview of how Rab proteins were lost during the expansion of eukaryotes. The losses of the putative last eukaryotic common ancestor (LECA) Rabs are indicated at each evolutionary step, as depicted in the key, with loss being indicated by loss of the black outline. The tree reflects available genome sequences rather than the full diversity of eukaroytic lineages. For the phyla with sufficient sequences available, we depict the losses during the evolution of a specific model organism. The extent of lost LECA Rab types varies considerably between different phyla. Whereas metazoans seem not to have lost any, the Apicomplexa have lost nine. Similarly, humans seem to have only lost two LECA Rabs, but S. cerevisiae has lost a total of fourteen.