Stimulus Perception in Bacterial Signal-Transducing Histidine Kinases

Abstract

SUMMARY Two-component signal-transducing systems are ubiquitously distributed communication interfaces in bacteria. They consist of a histidine kinase that senses a specific environmental stimulus and a cognate response regulator that mediates the cellular response, mostly through differential expression of target genes. Histidine kinases are typically transmembrane proteins harboring at least two domains: an input (or sensor) domain and a cytoplasmic transmitter (or kinase) domain. They can be identified and classified by virtue of their conserved cytoplasmic kinase domains. In contrast, the sensor domains are highly variable, reflecting the plethora of different signals and modes of sensing. In order to gain insight into the mechanisms of stimulus perception by bacterial histidine kinases, we here survey sensor domain architecture and topology within the bacterial membrane, functional aspects related to this topology, and sequence and phylogenetic conservation. Based on these criteria, three groups of histidine kinases can be differentiated. (i) Periplasmic-sensing histidine kinases detect their stimuli (often small solutes) through an extracellular input domain. (ii) Histidine kinases with sensing mechanisms linked to the transmembrane regions detect stimuli (usually membrane-associated stimuli, such as ionic strength, osmolarity, turgor, or functional state of the cell envelope) via their membrane-spanning segments and sometimes via additional short extracellular loops. (iii) Cytoplasmic-sensing histidine kinases (either membrane anchored or soluble) detect cellular or diffusible signals reporting the metabolic or developmental state of the cell. This review provides an overview of mechanisms of stimulus perception for members of all three groups of bacterial signal-transducing histidine kinases.

Two-component signal transduction systems in oral bacteria

“…There are also hybrid RRs (HRRs) containing HK domains [27,28]. There are 35 different families of RRs based on different types of output domains [22,26,29]. Approximately 50% of the activated RRs undergo homodimerization involving conserved residues at their receiver domains, and dimer formation is required for interaction with the regulatory regions of the target genes, which may contain tandem and inverted repeats [16,22].…”

“…Although sequence analyses of bacterial genomes reveals a diverse array of TCSs based on their conserved domain architecture, there is still limited information about their biological functions, and few studies have identified the stimuli responsible for HK activation [29]. Experimental studies and comparative genome analysis indicate that arrangement and topology of the N-terminal sensor and TM domains of HKs correlate with the type of stimuli sensed [30].…”

“…Examples of stimuli sensed by this group of HKs include cytoplasmic solutes or signalling proteins, stimuli transmitted through transmembrane proteins, or membrane-diffusible compounds [29]. Domain architectures of N-terminal and C-terminal regions of HKs of these three groups have been used to classify HKs of the three major groups into a relatively small number of sub-groups [29]. Few representatives of these sub-groups were functionally characterized, highlighting the need of functional studies on TCS.…”

Heavy Metal Detection and Removal in Artificial Wastewater Using Two-Component System Based Recombinant Bacteria

“…TCS는 원래 박테리아의 외부환경 감지 센 서로서 다양한 환경 변화를 감지하는 기능을 한다 (Stock et al, 2000). 각각의 TCS는 외부의 환경 변화를 감지하는 histidine kinase (HK)와 외부신호를 전달받아 관련 유전자의 발현을 유도 하는 response regulator (RR)로 구성되어 있다 (Mascher et al, 2006). 현재까지 밝혀진 TCS 중에서 ZraS/R은 외부의 Zn 2+ 를 감지하여 아연 efflux 연관 유전자인 zraP의 발현을 유도하여 균 주 내부의 아연 농도를 낮추고 항상성을 유지하는 역할을 수행…”

“…TCS는 원래 박테리아의 외부환경 감지 센 서로서 다양한 환경 변화를 감지하는 기능을 한다 (Stock et al, 2000). 각각의 TCS는 외부의 환경 변화를 감지하는 histidine kinase (HK)와 외부신호를 전달받아 관련 유전자의 발현을 유도 하는 response regulator (RR)로 구성되어 있다 (Mascher et al, 2006 한다. 또한 CusS/R TCS는 Cu 2+ 를 감지하여 구리 efflux와 연관된 cusC 유전자를 발현시킨다 (Munson et al, 2000;Leonhartsberger et al, 2001).…”