Cytoplasmic Lipid Membrane Biogenesis in Prokaryotes: From Soluble Lipid Building Blocks to a Dynamic and Functional Boundary Layer

Prokaryotic membranes are fundamental to cellular organization and function, serving as dynamic platforms for transport, energy conservation, signaling, environmental adaptation, etc. This review provides an overview of prokaryotic membrane architecture, highlighting the structural diversity of bacterial and archaeal cell envelopes, focusing on the cytoplasmic membranes and the distinct lipid chemistries that define them. By describing the general pathways for fatty acid and phospholipid biosynthesis, we emphasize the universal role for the lipid intermediates lysophosphatidic acid and phosphatidic acid, as well as the major lipid species phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin of the diderm bacteria Escherichia coli . Besides synthesis, lipid membrane insertion is described, highlighting recent findings regarding lipid leaflet distribution, asymmetry, and intermembrane transport. Altogether, these processes provide a general overview of lipid composition and function of proliferating cells.