Two-component signal transduction pathways are the primary mechanism by which bacteria adapt to different environmental conditions. The signal transduction pathway consists of a membrane sensor and a cytoplasmic regulatory protein. In the EnvZ-OmpR model system, EnvZ is
phosphorylated by ATP when the osmolarity of the environment increases. The subsequent phosphorylation of OmpR controls the differential expression of the ompF and ompC genes. The OmpF and OmpC proteins form diffusion channels through which nutrient pass into the cell.

Last Modified: February 26, 1999