A new paper was just published by my Computational Genomics Group at the Instituto Gulbenkian de Ciência in the prestigious journal Molecular Biology and Evolution, showing that the small GTPases in the newly found Archaeal phylum have many Rab-like properties, and that by co-existing with REP/GDI-like molecules, they allow us to propose that the interaction between Rabs and REP/GDIs proceeded the emergence of the lipid modification (geranygeranylation) that allows Rabs to operate as membrane associated molecular switches.
For the non-aficionado, it is the equivalent of finding an evolutionary intermediate state of a very complex sub-cellular machine. This allows us to understand how such complexity may have arisen in evolution.
The paper is published in Open Access form, and you can read it at Are there Rab GTPases in Archaea? This is the work of the PhD student Jaroslaw Surkont.