Organellogenesis: Host proteins control symbiont cell divisions.

Understanding the order and importance of events through which endosymbionts transition into cellular organelles (organellogenesis) is central to hypotheses about the origin of the eukaryotic cell. A new study on host-symbiont integration in a unicellular eukaryote reveals host-derived cell-division proteins that are targeted to the cell envelope of a bacterial endosymbiont and involved in its cell division.