Polyphosphate (polyP) is a ubiquitous polymer found in all cells from archaea, eubacteria, fungi, and protozoa to plants and mammals. PolyP is comprised of a linear chain of hundreds of phosphate residues linked by ATP-like, high-energy, phosphoanhydride metaphosphate) bonds. Several biological functions have been suggested for polyP, including a reservoir for phosphate and energy, a chelator of metal ions, a buffer against alkali, and a channel for DNA entry. PolyP also appears to have a role in two-component signal transduction, yet, its biological role is poorly understood. Complementary molecular genetic and physiology experiments will be carried out in the bacterium Escherichia coli with the goal of better understanding the function of polyP in cell biology. Experiments are being directed towards addressing two aims: the first is to define the genetic regulation of the polyP kinase (ppk)-polyP phosphatase (ppx) operon, and the second is to examine the consequences of rapidly increasing polyP levels on gene regulation in vivo.
