3.A.31.1.3
The ESCRT cell division complex consisting of CdvA, CdvB and CdvC (and maybe CdvB1,B2,B3). The majority of Crenarchaeota utilize the cell division system (Cdv) to divide. This system is encoded by three highly conserved genes, cdvA, cdvB and cdvC that are organized in an operon. The CdvA, CdvB and CdvC proteins polymerize between segregating nucleoids and persist throughout cell division, forming a successively smaller structure during constriction (Lindås et al. 2008). CdvA is a membrane interacting protein that recruits ESCRT-III homologs to the membrane (Samson et al. 2011).CdvC is homologous to the AAA-type ATPase Vps4, involved in multivesicular body biogenesis in eukaryotes. CdvA is a unique archaeal protein that interacts with the membrane, while CdvB is homologous to the eukaryal Vps24 and forms helical filaments. Most Crenarcheota contain additional CdvB paralogs. In Sulfolobus acidocaldarius these are termed CdvB1-3. Yang and Driessen 2014 used a gene inactivation approach to determine the impact of these additional cdvB genes on cell division. Independent deletion mutants of these genes were analyzed for growth and protein localization. One of the deletion strains (ΔcdvB3) showed a severe growth defect on plates and delayed growth on liquid medium. It yielded the formation of enlarged cells and a defect in DNA segregation. Since these defects are accompanied by an aberrant localization of CdvA and CdvB, it was concluded that CdvB3 fulfills an important accessory role in cell division.