The life cycle of an archaeon with multiple membranes

Prokaryotes, a diverse group of single-celled organisms, can be categorized into diderms. These organisms divide utilizing an FtsZ division ring, which simultaneously constricts the inner and outer membranes to create daughter cells, each possessing two membranes. Currently, it is known that only one archaeon, Ignicoccus hospitalis, possesses an outer and inner membrane. This study delves into the cell division process of I. hospitalis, utilizing expansion microscopy techniques.

The researchers found that I. hospitalis employs a contractile CdvA-ESCRT-III ring to repeatedly constrict and cut its inner membrane in a manner that results in clusters containing multiple cytoplasms within a shared periplasm. Following this, the outer bounding membrane bursts, releasing the progeny cells. These newly formed cells regain their original cell architecture through a process known as membrane duplication.

Interestingly, this life cycle appears to be conserved across various strains of Ignicoccus, despite the variation in the precise timing of events. The findings of this study suggest that I. hospitalis propagates through dynamic changes in its architecture as it transitions between single and multi-cellular states. In summary, this research provides valuable insights into the unique life cycle of Ignicoccus hospitalis, an archaeon with multiple membranes.