Tourte Maxime, Schaeffer Philippe, Grossi Vincent, Oger Phil M
Université de Lyon, INSA Lyon, CNRS, MAP UMR 5240, Villeurbanne, France.
Université de Strasbourg-CNRS, UMR 7177, Laboratoire de Biogéochimie Moléculaire, Strasbourg, France.
Front Microbiol. 2020 Mar 31;11:526. doi: 10.3389/fmicb.2020.00526. eCollection 2020.
Bacteria and Eukarya organize their plasma membrane spatially into domains of distinct functions. Due to the uniqueness of their lipids, membrane functionalization in Archaea remains a debated area. A novel membrane ultrastructure predicts that monolayer and bilayer domains would be laterally segregated in the hyperthermophilic archaeon . With very different physico-chemical parameters of the mono- and bilayer, each domain type would thus allow the docking of different membrane proteins and express different biological functions in the membrane. To estimate the ubiquity of this putative membrane ultrastructure in and out of the order Thermococcales, we re-analyzed the core lipid composition of all the Thermococcales type species and collected all the literature data available for isolated archaea. We show that all species of Thermococcales synthesize a mixture of diether bilayer forming and tetraether monolayer forming lipids, in various ratio from 10 to 80% diether in and , respectively. Since the domain formation prediction rests only on the coexistence of di- and tetraether lipids, we show that all Thermococcales have the ability for domain formation, i.e., differential functionalization of their membrane. Extrapolating this view to the whole Archaea domain, we show that almost all archaea also have the ability to synthesize di- and tetraether lipids, which supports the view that functionalized membrane domains may be shared between all Archaea. Hence domain formation and membrane compartmentalization may have predated the separation of the three domains of life and be essential for the cell cycle.
细菌和真核生物将其质膜在空间上组织成具有不同功能的结构域。由于古菌脂质的独特性，古菌中的膜功能化仍是一个存在争议的领域。一种新的膜超微结构预测，在嗜热古菌中单层和双层结构域将横向分离。由于单层和双层具有非常不同的物理化学参数，因此每种结构域类型都可以允许不同的膜蛋白对接，并在膜中表达不同的生物学功能。为了评估这种假定的膜超微结构在嗜热栖热菌目内外的普遍性，我们重新分析了所有嗜热栖热菌目模式种的核心脂质组成，并收集了所有可获得的关于分离古菌的文献数据。我们发现，所有嗜热栖热菌目物种都合成形成二醚双层和形成四醚单层的脂质混合物，在嗜热栖热菌和嗜热栖热放线菌中，二醚的比例分别为10%至80%。由于结构域形成的预测仅基于二醚和四醚脂质的共存，我们表明所有嗜热栖热菌目都具有形成结构域的能力，即其膜的差异功能化。将这一观点推广到整个古菌域，我们发现几乎所有古菌也都有合成二醚和四醚脂质的能力，这支持了功能化膜结构域可能在所有古菌中共享的观点。因此，结构域形成和膜区室化可能在生命的三个域分离之前就已存在，并且对细胞周期至关重要。
