Bacterial hybrid histidine kinases in plant–bacteria interactions

Abstract

Two-component signal transduction systems are essential for many bacteria to maintain homeostasis and adapt to environmental changes. Two-component signal transduction systems typically involve a membrane-bound histidine kinase that senses stimuli, autophosphorylates in the transmitter region and then transfers the phosphoryl group to the receiver domain of a cytoplasmic response regulator that mediates appropriate changes in bacterial physiology. Although usually found on distinct proteins, the transmitter and receiver modules are sometimes fused into a so-called hybrid histidine kinase (HyHK). Such structure results in multiple phosphate transfers that are believed to provide extra-fine-tuning mechanisms and more regulatory checkpoints than classical phosphotransfers. HyHK-based regulation may be crucial for finely tuning gene expression in a heterogeneous environment such as the rhizosphere, where intricate plant-bacteria interactions occur. In this review, we focus on roles fulfilled by bacterial HyHKs in plant-associated bacteria, providing recent findings on the mechanistic of their signalling properties. Recent insights into understanding additive regulatory properties fulfilled by the tethered receiver domain of HyHKs are also addressed.

Goals and Challenges in Bacterial Phosphoproteomics

“…For instance, Streptomyces coelicolor harbours more than 100 two-component signalling systems (), many of which regulate secondary metabolism and antibiotic production [72]. Bacterial two-component systems modulate important cellular processes, such as photoreception [73], quorum sensing [74], temperature sensing [75] and plant-bacteria interactions [76].…”

Stenotrophomonas maltophilia as an Emerging Ubiquitous Pathogen: Looking Beyond Contemporary Antibiotic Therapy

“…The activities of the S. maltophilia in the root rhizosphere are beneficial (Ryan et al, 2009 ; Mendes et al, 2013 ; Alavi et al, 2014 ). This is because, the bacteria exert positive effects in plant growth and health, bioremediation and phytoremediation and synthesis of valuable macromolecules (Ting and Choong, 2009 ; Borland et al, 2016 ).…”

Orphan Hybrid Histidine Protein Kinase SinK Acts as a Signal Integrator To Fine-Tune Multicellular Behavior in Myxococcus xanthus

“…Examples include the RodK/RokA system, consisting of a triple receiver hybrid histidine kinase and single-domain response regulator that influence appropriate localization of spores within fruiting bodies (22,34); the EspA/EspC system, hybrid histidine kinases that cross-phosphorylate to regulate appropriate timing and spore location via turnover of the major transcription factor MrpC (25,35); the RedCDEF four-component system necessary for appropriate aggregation timing (23); the CrdA/S system necessary for appropriate developmental entry (24); the PilSR/S 2 R 2 system necessary for coordinated type 4 pilus regulation (26); and the FrzE/FrzZ/FrzX system that serves to coordinate cell reversals necessary for M. xanthus-directed movement (36). These complex integrated strategies appear to be common in environmental bacteria and likely allow for integrated responses to rapidly changing environmental conditions (37).…”