RICHLAND, Wash. -- Time-lapsed video of individual breast tissue cells reveals a never-before-seen event in the life of a cell: a protein that cycles between two major compartments in the cell. The results give researchers a more complete view of the internal signals that cause breast tissue cells to grow, events that go awry in cancer and are targets of drug development.
The protein ERK, which helps cells respond to growth factors, travels back and forth between the nucleus, where genes are turned on and off, and the cell proper, where proteins work together to keep the cell functioning. In the video, individual cells pulsate with green light as an engineered fluorescent ERK fills the nucleus, exits and re-enters again in cycles that take about 15 minutes. The researchers don't know if the oscillation affects the activity of other proteins in a regulatory fashion, they report in December 1 issue of Molecular Systems Biology, but find the oscillations to be regular and robust.
"True oscillations in biology are rare," said lead author Steve Wiley, chief biologist at EMSL, located at the Department of Energy's Pacific Northwest National Laboratory. "And that the oscillations of such a major growth regulator could go undiscovered for so long is extremely surprising."
ERK As Anchor
One possible function of the oscillations could be in regulating how ERK interacts with other proteins. Regardless of its biological function, ERK oscillations between compartments represent a new behavior that proteins can exhibit within cells.
Biomedical researchers need an accurate mathematical model in hand to test anti-cancer drugs. Adding ERK oscillations into the model allowed Wiley's group to make better predictions about how breast cells will respond to changes in their environment, such as the presence of growth factors or cancer drugs.
"Current models used in drug development behave very differently from
|Contact: Mary Beckman|
DOE/Pacific Northwest National Laboratory