Extensive molecular tinkering in the evolution of the membrane attachment mode of the Rheb GTPase.

Rheb is a conserved and widespread Ras-like GTPase involved in cell growth regulation mediated by the (m)TORC1 kinase complex and implicated in tumourigenesis in humans. Rheb function depends on its association with membranes via prenylated C-terminus, a mechanism shared with many other eukaryotic GTPases. Strikingly, our analysis of a phylogenetically rich sample of Rheb sequences revealed that in multiple lineages this canonical and ancestral membrane attachment mode has been variously altered.

A Eukaryote without a Mitochondrial Organelle.

The presence of mitochondria and related organelles in every studied eukaryote supports the view that mitochondria are essential cellular components. Here, we report the genome sequence of a microbial eukaryote, the oxymonad Monocercomonoides sp., which revealed that this organism lacks all hallmark mitochondrial proteins.

A paneukaryotic genomic analysis of the small GTPase RABL2 underscores the significance of recurrent gene loss in eukaryote evolution.

Background: The cilium (flagellum) is a complex cellular structure inherited from the last eukaryotic common ancestor (LECA). A large number of ciliary proteins have been characterized in a few model organisms, but their evolutionary history often remains unexplored. One such protein is the small GTPase RABL2, recently implicated in the assembly of the sperm tail in mammals.