The Role of Lipid Domains in Bacterial Cell Processes

Abstract

Membranes are vital structures for cellular life forms. As thin, hydrophobic films, they provide a physical barrier separating the aqueous cytoplasm from the outside world or from the interiors of other cellular compartments. They maintain a selective permeability for the import and export of water-soluble compounds, enabling the living cell to maintain a stable chemical environment for biological processes. Cell membranes are primarily composed of two crucial substances, lipids and proteins. Bacterial membranes can sense environmental changes or communication signals from other cells and they support different cell processes, including cell division, differentiation, protein secretion and supplementary protein functions. The original fluid mosaic model of membrane structure has been recently revised because it has become apparent that domains of different lipid composition are present in both eukaryotic and prokaryotic cell membranes. In this review, we summarize different aspects of phospholipid domain formation in bacterial membranes, mainly in Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. We describe the role of these lipid domains in membrane dynamics and the localization of specific proteins and protein complexes in relation to the regulation of cellular function.

The copYAZ Operon Functions in Copper Efflux, Biofilm Formation, Genetic Transformation, and Stress Tolerance in Streptococcus mutans

“…Our findings are in agreement with those of another study, where the loss of the arsenic and antimony efflux system in E. coli was shown to be linked with cell membrane depolarization (91). Disturbances in the bacterial membrane potential can alter certain cellular processes, such as cell division and differentiation, maintenance of the integrity of cellular membranes, electron transport across the membranes, localization of specific proteins and protein complexes, and regulation of the levels of cellular energy (86,(92)(93)(94). In S. mutans, copper acting as a membrane potential dissipater might contribute to the generation of copper-dependent oxidative and acid stress, where both these stresses are likely to be affected by variations in the bacterial membrane integrity and/or changes in electron transport across the bacterial membrane (87,(95)(96)(97).…”

Identification of specific posttranslational O -mycoloylations mediating protein targeting to the mycomembrane

“…More importantly, we identified the O-acylation motif in a larger panel of C. glutamicum proteins involved in the biogenesis of the cell envelope, including mycoloyltransferases, an acyl transferase, and a peptidoglycan hydrolase, or the maintenance of its integrity, such as lipocalin and flotillin. Whereas the two latter proteins are known to be acylated in Escherichia coli via an amide linkage (26)(27)(28)(29), other proteins, including the mycoloyltransferases, have only been characterized in their soluble, nonacylated forms (7,30,31). Furthermore, we showed a physicochemical similarity in the properties of the O-acylation sites between Corynebacteriales and two human proteins (i.e., the ghrelin and Wnt-3a).…”

The Histidine Residue of QseC Is Required for Canonical Signaling between QseB and PmrB in Uropathogenic Escherichia coli

“…Control of TCS signaling is achieved via several means, including protein stability, sensor histidine kinase-response regulator protein-protein interactions, and spatial tethering, as well as protein stoichiometry (21)(22)(23)(24)(25). In phosphorelay systems, complexity is even higher, encompassing the use of accessory proteins that mediate phosphorylation/dephosphorylation events in response to different cues (26,27).…”