A chemoreceptor from Pseudomonas putida forms active signalling complexes in Escherichia coli

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Bacterial chemoreceptors are crucial for sensing environmental stimuli and directing motility via flagellar motors.
• Chemoreceptor cytoplasmic domains, featuring conserved α-helical hairpins, exhibit variable lengths defining distinct classes.
• Signal transduction involves histidine kinase regulation of CheY phosphorylation.

Purpose of the Study:

• To investigate the functional compatibility of a Pseudomonas chemoreceptor within the Escherichia coli signaling system.
• To determine if foreign chemoreceptors can form active signaling complexes with non-cognate E. coli proteins.
• To assess the adaptive capabilities of such chimeric signaling complexes.

Main Methods:

• Assembly of a Pseudomonas chemoreceptor with E. coli signaling proteins.
• Functional analysis of chemotaxis in E. coli cells expressing the chimeric complex.
• Assessment of stimulus-induced modulation of kinase activity and adaptation mechanisms.

Main Results:

• The Pseudomonas receptor did not restore full chemotaxis in E. coli.
• Active ternary signaling complexes were formed, responding to specific stimuli.
• Modulation of kinase activity was observed, indicating functional signal transduction.
• Responses were subject to adaptation, dependent on CheR and CheB methylation enzymes.

Conclusions:

• Foreign chemoreceptors can functionally integrate with heterologous bacterial signaling machinery.
• This cross-species signaling capability allows the use of well-characterized systems like E. coli to study uncharacterized chemoreceptors.
• The findings highlight the potential for utilizing E. coli as a platform to decipher the detection specificities of diverse microbial chemoreceptors.