Original data-Widespread PRC barrel proteins are necessary for haloarchaeal cell division.zip

Cell division is fundamental to all cellular life. Most archaea depend on either the prokaryotic tubulin homolog FtsZ, or the endosomal sorting complex required for transport (ESCRT) for division, but neither system has been robustly characterized. Here, we show that three of the four PRC (Photosynthetic Reaction Center) barrel domain proteins of<i> Haloferax volcanii</i> (renamed Cell division proteins B1/2/3 (CdpB1/2/3)), play important roles in cell division. CdpB1 interacts directly with the FtsZ membrane anchor SepF and is essential for cell division, whereas deletion of <i>cdpB2</i> and <i>cdpB3</i> causes a major and a minor division defect, respectively. Orthologs of CdpB proteins are also involved in cell division in other haloarchaea, indicating a conserved function of these proteins. Phylogenetic analysis shows that PRC barrel proteins are widely distributed among archaea, and appear to be central to cell division in most if not all archaea.