Cellular Mechanosensation and Osmoregulation
Biology and Chemistry departments
New York University
Bacteria can thrive in fluctuating and extreme environments. Thus, a central question in biology concerns the mechanisms by which bacteria can adapt to stresses and the strategies they use for that purpose. Regulation of the internal and external osmotic forces across the cell membrane is one of the most fundamental processes bacteria employ to survive changes in the media osmolarity. At the center of this homeostatic strategy is the gating of mechanosensitive (MS) channels embedded in the plasma membrane of bacteria. We study cell survival in environments fluctuating in osmolyte concentrations using Bacillus Subtilis as a model system.
Mechanical Interactions with the Environment
In vivo, eukaryotic cells are embedded in a matrix environment, where they grow and develop. Generally, this extracellular matrix (ECM) is an anisotropic fibrous structure, through which macromolecules and biochemical signaling molecules at the nanometer scale diffuse. The ECM is continuously remodeled by cells, via mechanical interactions, which lead to a potential link between biomechanical and biochemical cell–cell interactions.
Effects of Molecular Crowding in Biological Systems
The interior of cells is a crowded environment, quite different from the dilute solutions usually studied in vitro. For example, in bacterial cells, macromolecules can occupy up to 40 % of the volume during phases of rapid growth, and the water content can drop far below this level upon exposure to increased osmotic pressure. The importance of molecular crowding for understanding processes in cells is increasingly appreciated.