Genome-Wide Functional Screen for Calcium Transients in Escherichia coli Identifies Increased Membrane Potential...

Area of Science:

• Bacterial Physiology
• Cellular Signaling
• Molecular Biology

Background:

• Calcium is vital for eukaryotic cell signaling and homeostasis, but its roles in bacteria are less understood.
• Previous studies in Escherichia coli linked calcium influx to voltage changes and mechanical stimulation, suggesting a role in mechanosensation.
• Identifying genes controlling bacterial calcium handling is crucial for understanding these processes.

Purpose of the Study:

• To identify genes regulating cytoplasmic calcium dynamics in Escherichia coli.
• To refine models of electrophysiology-mediated bacterial mechanosensation.
• To investigate the relationship between DNA damage response and calcium signaling.

Main Methods:

• A genome-wide knockout panel of Escherichia coli (Keio collection) was screened.
• Live-cell imaging was used to monitor calcium transients in single cells.
• Calcium dynamics were quantified across the knockout population.

Main Results:

• 143 gene knockouts decreased calcium transients; 32 increased them.
• Proteins involved in energy production, F1Fo-ATPase, exopolysaccharide, and outer membrane synthesis were identified.
• Knockouts of DNA repair proteins showed reduced calcium transients and voltage, particularly in long-term DNA damage adaptation.

Conclusions:

• The study identified novel genes involved in bacterial calcium handling and mechanosensation.
• Findings refined the model of voltage-mediated bacterial mechanosensation.
• A distinction between acute and long-term DNA damage responses in bacteria was revealed, with implications for eukaryotes.