Phosphatidylglycerol-rich bacterial membrane domains (PG-rich domains)

Phosphatidylglycerol-rich bacterial membrane domains are specialized, anionic regions within the bacterial cytoplasmic membrane that serve as critical organizational platforms for various physiological processes. These domains are characterized by a high density of phosphatidylglycerol (PG), which facilitates the recruitment and regulation of essential membrane-associated proteins involved in cell division, such as FtsZ and MinD, and cell wall biosynthesis (Müller et al., 2016; Epand et al., 2016). In Gram-positive pathogens like Staphylococcus aureus, these domains are vital for maintaining membrane potential and structural stability. They represent a significant therapeutic target for several classes of antibiotics, most notably the cyclic lipopeptide daptomycin, which requires PG for its calcium-dependent insertion and subsequent oligomerization within the membrane (Humphries et al., 2013). This interaction leads to membrane depolarization, leakage of intracellular ions, and the displacement of peripheral membrane proteins, resulting in rapid bacterial cell death (Pader et al., 2016). While these domains offer a degree of selectivity due to the lower PG content in the outer leaflet of mammalian cells, their similarity to mitochondrial membranes presents a potential challenge for drug safety and development (Seydlová et al., 2019).

Other names

Anionic lipid domainsPG-rich microdomainsBacterial lipid raftsFunctional membrane microdomainsPhosphatidylglycerol domains

Antibiotics targeting these domains typically utilize a multi-step process involving initial electrostatic attraction to the anionic PG headgroups, followed by calcium-dependent insertion or hydrophobic interaction, leading to membrane oligomerization, pore formation, and lethal depolarization of the bacterial cell membrane (Humphries et al., 2013; Müller et al., 2016).