Role of Regulated Proteolysis in the Communication of Bacteria With the Environment

Abstract

For bacteria to flourish in different niches, they need to sense signals from the environment and translate these into appropriate responses. Most bacterial signal transduction systems involve proteins that trigger the required response through the modification of gene transcription. These proteins are often produced in an inactive state that prevents their interaction with the RNA polymerase and/or the DNA in the absence of the inducing signal. Among other mechanisms, regulated proteolysis is becoming increasingly recognized as a key process in the modulation of the activity of these signal response proteins. Regulated proteolysis can either produce complete degradation or specific cleavage of the target protein, thus modifying its function. Because proteolysis is a fast process, the modulation of signaling proteins activity by this process allows for an immediate response to a given signal, which facilitates adaptation to the surrounding environment and bacterial survival. Moreover, regulated proteolysis is a fundamental process for the transmission of extracellular signals to the cytosol through the bacterial membranes. By a proteolytic mechanism known as regulated intramembrane proteolysis (RIP) transmembrane proteins are cleaved within the plane of the membrane to liberate a cytosolic domain or protein able to modify gene transcription. This allows the transmission of a signal present on one side of a membrane to the other side where the response is elicited. In this work, we review the role of regulated proteolysis in the bacterial communication with the environment through the modulation of the main bacterial signal transduction systems, namely one-and two-component systems, and alternative σ factors.

dSeqSb: A systems biology approach to decipher dynamics of host-pathogen interactions using temporal dual RNA-seq data

“…This process can stimulate the response of the innate immune system (47). GO enrichment analysis has shown that 380 genes across host clusters were enriched with functions which play essential roles in mediating cellular entry of pathogens ( e.g ., epidermal growth factor receptor (EGFR) signalling pathway (48), growth hormone receptor signalling pathway (49), mitochondrial ATP synthesis coupled electron transport (50), protein targeting to endoplasmic reticulum(51)), communication of bacteria with the host environment ( e.g ., positive regulation of establishment of protein localization(52)), control of infection ( e.g ., regulation of protein metabolic process(53)), invading pathogen ( e.g ., response to laminar fluid shear stress (54)), and co-opting host factors ( e.g ., viral gene expression (55)) that can be considered as potential targets in designing antibacterial therapies. Enriched functions were mostly observed at 24h and 4h pi in the host and pathogen, respectively, with mainly downregulated expression (Supplementary Table).…”

The Role of Pseudo-Orthocaspase (SyOC) of Synechocystis sp. PCC 6803 in Attenuating the Effect of Oxidative Stress

“…PCC 6803 has been extensively studied after exposure to various stresses; however, while sensor histidine kinases (Hik), small CAB-like proteins (S), or proteases like HtrA, Clp, or FtsH are known regulators of protein homeostasis in photosynthetic prokaryotes ( Stanne et al, 2007 ; Tryggvesson et al, 2012 ; Cheregi et al, 2016 ; Tibiletti et al, 2018 ; Huang et al, 2019 ), pseudo-enzymes, particularly SyOC, have so far escaped detection. Regulated proteolytic activity is an essential mechanism of signal transduction used by peptidases to cleavage substrates and response to external stimuli ( Wettstadt and Llamas, 2020 ). Nevertheless, our results highlight the relevance of pseudo-enzymes in maintaining internal homeostasis.…”

Recent Advances in the Mechanisms and Regulation of QS in Dairy Spoilage by Pseudomonas spp.

“…Some of the genes upregulated by C6-HSL were elongation factors and sec/yaj C/ yid C, responsible for protein synthesis and secretion, respectively; the type VI secretion system T4SS used for the transport of proteins and DNA across the cell envelope; and lip S, muc D, and the probable periplasmic serine endoprotease DegP-like (PputW619_1070). In Gram-negative bacteria (e.g., E. coli ), DegP serine endoproteases are involved in regulated intramembrane proteolysis (RIP) cleaving transmembrane proteins to liberate a cytosolic domain of proteins able to modify gene transcription, such as the two-component regulatory system CpxA/CpxR, which responds to envelope stress response [ 136 ].…”