Adaptive tuning of cell sensory diversity without changes in gene expression

Area of Science:

• Microbiology
• Systems Biology
• Cellular Dynamics

Background:

• Cell populations diversify phenotypes to enhance survival under uncertain conditions.
• Previous research focused on gene expression for bet hedging; this study explores posttranslational modifications.
• Phenotypic diversity is crucial for adapting to environmental changes.

Purpose of the Study:

• To investigate the role of posttranslational modifications in tuning cellular phenotypic diversity.
• To understand how Escherichia coli modulates response sensitivity in its chemotaxis network.
• To reveal mechanisms cells use for bet hedging beyond gene expression.

Main Methods:

• Experimental analysis of chemoreceptors Tar and Tsr in Escherichia coli.
• Mathematical modeling of cellular response dynamics.
• Investigating cell-to-cell variation in response sensitivity.

Main Results:

• Posttranslational modifications dynamically tune cell-to-cell variation in chemoreceptor sensitivity.
• This tuning depends on the presence or absence of chemoeffector ligands.
• Diversity tuning relies on environment-dependent covalent modification and allosteric coupling variation.

Conclusions:

• Posttranslational modifications are a key mechanism for tuning phenotypic diversity in cell populations.
• Phenotypic diversity enhances population readiness for diverse signals when cues are absent.
• Upon signal detection, the population shifts focus to efficiently track the perceived signal.