Experimental measurement and computational prediction of bacterial Hanks-type Ser/Thr signaling system regulatory targets.

Bacteria possess diverse classes of signaling systems that they use to sense and respond to their environments and execute properly timed developmental transitions. One widespread and evolutionarily ancient class of signaling systems are the Hanks-type Ser/Thr kinases, also sometimes termed "eukaryotic-like" due to their homology with eukaryotic kinases. In diverse bacterial species, these signaling systems function as critical regulators of general cellular processes such as metabolism, growth and division, developmental transitions such as sporulation, biofilm formation, and virulence, as well as antibiotic tolerance.

Modular and Single-Cell Sensors of Bacterial Ser/Thr Kinase Activity.

At the single-cell level, protein kinase activity is typically inferred from downstream transcriptional reporters. However, promoters are often coregulated by several pathways, making the activity of a specific kinase difficult to deconvolve. Here, we present modular, direct, and specific sensors of bacterial kinase activity, including FRET-based sensors, as well as a synthetic transcription factor based on the lactose repressor (LacI) that has been engineered to respond to phosphorylation.

Multisite phosphorylation drives phenotypic variation in (p)ppGpp synthetase-dependent antibiotic tolerance.

Isogenic populations of cells exhibit phenotypic variability that has specific physiological consequences. Individual bacteria within a population can differ in antibiotic tolerance, but whether this variability can be regulated or is generally an unavoidable consequence of stochastic fluctuations is unclear. Here we report that a gene encoding a bacterial (p)ppGpp synthetase in Bacillus subtilis, sasA, exhibits high levels of extrinsic noise in expression.

Habits of Highly Effective Biofilms: Ion Signaling.

How do neighboring bacterial biofilms sense and communicate with each other? In a recent paper, Liu et al. (2017) demonstrate how electrical signaling allows communication of metabolic states between adjacent B. subtilis biofilms, providing a possible generalizable mechanism for communication in multispecies biofilms with interdependent metabolism.

In Vivo Probe of Lipid II-Interacting Proteins.

β-Lactams represent one of the most important classes of antibiotics discovered to date. These agents block Lipid II processing and cell wall biosynthesis through inactivation of penicillin-binding proteins (PBPs). PBPs enzymatically load cell wall building blocks from Lipid II carrier molecules onto the growing cell wall scaffold during growth and division.

The Eukaryotic-Like Ser/Thr Kinase PrkC Regulates the Essential WalRK Two-Component System in Bacillus subtilis.

Most bacteria contain both eukaryotic-like Ser/Thr kinases (eSTKs) and eukaryotic-like Ser/Thr phosphatases (eSTPs). Their role in bacterial physiology is not currently well understood in large part because the conditions where the eSTKs are active are generally not known. However, all sequenced Gram-positive bacteria have a highly conserved eSTK with extracellular PASTA repeats that bind cell wall derived muropeptides.

Membrane protein expression triggers chromosomal locus repositioning in bacteria.

It has long been hypothesized that subcellular positioning of chromosomal loci in bacteria may be influenced by gene function and expression state. Here we provide direct evidence that membrane protein expression affects the position of chromosomal loci in Escherichia coli. For two different membrane proteins, we observed a dramatic shift of their genetic loci toward the membrane upon induction.

The quality of warfarin prescribing and monitoring in Veterans Affairs nursing homes.

Objectives: To describe the quality of warfarin prescribing and monitoring in Veterans Affairs (VA) nursing homes and to assess the factors associated with maintaining a therapeutic international normalized ratio (INR).

Design: Retrospective cohort.

Setting: Five VA nursing homes.

Imaging OmpR binding to native chromosomal loci in Escherichia coli.

Previously, an unexplained subcellular localization was reported for a functional fluorescent protein fusion to the response regulator OmpR in Escherichia coli. The pronounced regions of increased fluorescence, or foci, are dependent on OmpR phosphorylation and do not occupy fixed, easily identifiable positions, such as the poles or mid-cell. Here we show that the foci are due to OmpR-YFP (yellow fluorescent protein) fusion binding to specific sites in the chromosome.