All living organisms share the need to replicate and proliferate to ensure the survival of their species. In prokaryotes, this is generally guaranteed by a process of cell division where a mother cell is split into two equally sized daughter cells, and it is a complex and heterogeneous process across all the different species. When looking into the Crenarchaea phylum of the archaea, we find a very particular set of proteins that are responsible for orchestrating this process of cell division: the Cdv system. This system is closely related to the ESCRT machinery, which is also responsible for cell division and many other membrane deforming processes in eukaryotes. This close similarity is one of the many common traits that point towards a common origin between archaea and eukaryotes. Although the eukaryotic machinery has been thoroughly and extensively studied, very little is known about the archaeal division system. For this reason, in this work we aimed at better understanding these archaeal proteins, making use of in vitro techniques, with the long-term view of using them to build a synthetic cell form the bottom up...@en

The Cdv proteins constitute the cell division system of the Crenarchaea, a machinery closely related to the ESCRT system of eukaryotes. Using a combination of TEM imaging and biochemical assays, we here present an in vitro study of Metallosphaera sedula CdvB1, the Cdv protein that is believed to play a major role in the constricting ring that drives cell division in the Crenarchaea. We show that CdvB1 self-assembles into filaments that are depolymerized by the Vps4-homolog ATPase CdvC. Furthermore, we find that CdvB1 binds to negatively charged lipid membranes and can be detached from the membrane by the action of CdvC. Our findings provide novel insight into one of the main components of the archaeal cell division machinery.@en

The Cdv system is the protein machinery that performs cell division and other membrane-deforming processes in a subset of archaea. Evolutionarily, the system is closely related to the eukaryotic ESCRT machinery, with which it shares many structural and functional similarities. Since its first description 15 years ago, the understanding of the Cdv system progressed rather slowly, but recent discoveries sparked renewed interest and insights. The emerging physical picture appears to be that CdvA acts as a membrane anchor, CdvB as a scaffold that localizes division to the mid-cell position, CdvB1 and CvdB2 as the actual constriction machinery, and CdvC as the ATPase that detaches Cdv proteins from the membrane. This paper provides a comprehensive overview of the research done on Cdv and explains how this relatively understudied machinery acts to perform its cell-division function. Understanding of the Cdv system helps to better grasp the biophysics and evolution of archaea, and furthermore provides new opportunities for the bottom-up building of a divisome for synthetic cells.

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