Quantitative Modeling of Flagellar Motor-Mediated Adaptation

Area of Science:

• Microbiology
• Biophysics
• Systems Biology

Background:

• Bacterial chemotaxis allows cells to sense and move towards chemical attractants.
• The flagellar motor's response to chemoattractants is regulated by phospho-CheY (CheY-P) levels.
• Cell-to-cell variability in protein abundance can affect chemotaxis network sensitivity.

Purpose of the Study:

• To explain the mechanisms of switch remodeling and motor-mediated adaptation in bacterial flagellar motors.
• To understand how flagellar motor adaptation complements receptor-mediated adaptation in chemotaxis.
• To investigate how structural changes in the motor modulate protein binding and sensitivity.

Main Methods:

• A modeling approach is used to explain adaptation mechanisms.
• Analysis of structural differences in the flagellar motor switch complex.
• Investigating the modulation of FliM/FliN binding strength based on motor rotation direction.

Main Results:

• Switch remodeling allows flagellar motors to adapt to extracellular chemical stimuli.
• Remodeling complements receptor-mediated adaptation, maintaining motor sensitivity to CheY-P.
• Modulating CheY-P binding sites through remodeling optimizes motor sensitivity across signal levels.

Conclusions:

• Switch remodeling is a key mechanism for bacterial flagellar motor adaptation.
• This adaptation ensures robust chemotaxis despite variations in protein levels.
• The motor's ability to remodel enhances its sensitivity to chemical gradients.