The LECA Rabs and their proposed functions. A schematic LECA cell is shown with the routes controlled by the six Rab supergroups defined by Klöpper et al.  color-coded. The Rabs belonging to the respective groups are indicated below. Even though most of the Rabs have been retained in human cells, two have been lost (RabX1 and Rab29). Note that even if there is a good match between the phylogenetic grouping and the cellular pathways controlled by the respective Rabs, there are some possible misfits: Rab24 (group II) has been found to regulate autophagy; Rab23 (group III) has been described to regulate ciliary functions; Rab2 (group IV) was identified as a regulator of traffic in the early biosynthetic pathway; Rab6 (group V) has, in addition to regulating endosome-to-Golgi transport, also been implicated in intra-Golgi trafficking (see references in ). ER, endoplasmic reticulum.