Cellular and organellar membrane-associated proteins in haloarchaea： Perspectives on the physiological significance and biotechnological applications

Halophilic archaea （haloarchaea） inhabit hypersaline environments, tolerating extreme salinity, low oxygen and nutrient avail- ability, and in some cases, high pH （soda lakes） and irradiation （saltern ponds）. Membrane-associated proteins of haloarchaea, such as surface layer （S-layer） proteins, transporters, retinal proteins, and internal organellar membrane proteins including in- tracellular gas vesicle proteins and those associated with polyhydroxyalkanoate （PHA） granules, contribute greatly to their en- vironmental adaptations. This review focuses on these haloarchaeal cellular and organellar membrane-associated proteins, and provides insight into their physiological significance and biotechnological potential.