Structural biology - Synchronized division proteins

A new connection between eukaryotic mitosis and prokaryotic cell division may have been forged with the structures of two GTPases, which seem to be remarkably similar. The first is the tubulin heterodimer -- a protein that assembles into the microtubules involved in eukaryotic mitosis. And the second, FtsZ, forms a filamentous septum during prokaryotic cell division. Could this just be a coincidence, or does it reflect a common ancestry, indicating conservation of functional properties too?