Mechanosensitive Self-Assembly of Flagellar Stator Proteins in Bacteria
Abstract
Project Abstract Bacterial motility is powered by a tiny, rotary motor called the bacterial flagellar motor. Although the role of the flagellar motor in chemotaxis (migration towards or away from chemicals) and motility is well understood, recent discoveries suggest a crucial role for the flagellum in mechanical-sensing of substrates (mechanosensing). Evidence suggests that such sensing subsequently triggers the expression of genes involved in infections and colonization. Employing single-molecule measurement techniques and optical tweezers, we have identified a protein element in the motor that functions as a mechanosensor. Our observations also suggest that the sensor-complex undergoes remodeling (modifications in self-assembly) when mechanically stimulated. However, the molecular underpinnings responsible for mechanosensing and for the subsequent adaptation in motor-function remain unclear. Our objective is to determine the molecular mechanisms whereby mechanical signals that originate in the extracellular environment modulate the self-organization and functioning of large protein complexes in flagellar motors. Our central hypothesis is that the mechanochemical cycles responsible for torque-generation control motor-mechanosensitivity and remodeling. We will test this and competing hypotheses to explain how motor-proteins bind to their targets when motors are mechanically stimulated, and explain the role of protein-exchange in remodeling of specific protein complexes. We will also determine how the structure of specific proteins influences binding affinities and protein-exchange. To do this research, we will employ fluorescence techniques (total internal reflection fluorescence and fluorescence recovery after photobleaching), optical tweezer, molecular genetics and predictive modeling/computational analysis. Broadly, our results are expected to provide fundamental insights into the role of protein structures and exchange in mechanosensitivity. The rationale for the proposed work is that an understanding of these mechanisms will provide a conceptual framework for the design of protein-based synthetic systems, which will integrate with sophisticated sensors that respond and adapt to the application of mechanical forces. It is anticipated that such systems will provide enhanced signal-detection capabilities and remote-surgical services in the field.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 01, 2019
- Source ID
- W911NF1810353
Entities
People
- Pushkar P Lele
Organizations
- Army Contracting Command
- Texas Engineering Experiment Station
- United States Army