RcsF-independent mechanisms of signaling within the Rcs phosphorelay.

The Rcs (regulator of capsule synthesis) phosphorelay is a conserved cell envelope stress response mechanism in enterobacteria. It responds to perturbations at the cell surface and the peptidoglycan layer from a variety of sources, including antimicrobial peptides, beta-lactams, and changes in osmolarity. RcsF, an outer membrane lipoprotein, is the sensor for this pathway and activates the phosphorelay by interacting with an inner membrane protein IgaA.

How Does the Alarmone ppGpp Change Bacterial Cell Metabolism? From Genome-wide Approaches to Structure to Physiology.

Wang et al. (2020) show that binding of the second messenger ppGpp to inosine-guanosine kinase (Gsk) in E. coli modulates the levels of the key metabolite phosphoribosyl pyrophosphate (pRpp), decreasing purine synthesis to favor amino acid synthesis during stress adaptation.

Tracking the homeostasis of second messenger cyclic-di-GMP in bacteria.

Cyclic-di-GMP (c-di-GMP) is an important second messenger in bacteria which regulates the bacterial transition from motile to sessile phase and also plays a major role in processes such as cell division, exopolysaccharide synthesis, and biofilm formation. Due to its crucial role in dictating the bacterial phenotype, the synthesis and hydrolysis of c-di-GMP is tightly regulated via multiple mechanisms. Perturbing the c-di-GMP homeostasis affects bacterial growth and survival, so it is necessary to understand the underlying mechanisms related to c-di-GMP metabolism.

RelZ-Mediated Stress Response in : pGpp Synthesis and Its Regulation.

Stringent response is a conserved stress response mechanism in which bacteria employ the second messengers guanosine tetraphosphate and guanosine pentaphosphate [collectively termed (p)ppGpp] to reprogram their cellular processes under stress. In mycobacteria, these alarmones govern a multitude of cellular phenotypes, such as cell division, biofilm formation, antibiotic tolerance, and long-term survival. possesses the bifunctional Rel as a (p)ppGpp synthetase and hydrolase.

Antibiotic Resistance: Current Perspectives.

Antibiotic resistance is one of the most serious challenges that the world is currently facing. The number of people succumbing to drug-resistant infections is increasing every day, but the rate of drug discovery has failed to match the requisite demands. Most of the currently known antibiotics target the three essential pathways of central dogma.

Pup recycling regulates the proteasome.

The Pup proteasome system (PPS) in bacteria is equivalent to the eukaryotic ubiquitin proteasome system (UPS) that allows controlled protein degradation. Unlike the UPS, however, the PPS machinery and regulation is still poorly understood. In this issue of The FEBS Journal, Gur and colleagues combine experimental and modelling analyses to show how the PPS maintains steady-state levels of protein pupylation and consequently tightly controlled protein degradation.

R-loop induced stress response by second (p)ppGpp synthetase in Mycobacterium smegmatis: functional and domain interdependence.

Persistent R-loops lead to replicative stress due to RNA polymerase stalling and DNA damage. RNase H enzymes facilitate the organisms to survive in the hostile condition by removing these R-loops. MS_RHII-RSD was previously identified to be the second (p)ppGpp synthetase in Mycobacterium smegmatis.

Quorum sensing and biofilm formation in mycobacteria: role of c-di-GMP and methods to study this second messenger.

Bacteria have evolved to survive the ever-changing environment using intriguing mechanisms of quorum sensing (QS). Very often, QS facilitates formation of biofilm to help bacteria to persist longer and the formation of such biofilms is regulated by c-di-GMP. It is a well-known second messenger also found in mycobacteria.