A switch that controls whether cells pass point of...( DURHAM N.C. Investigators at the Du...)

DURHAM, N.C. Investigators at the Duke Institute for Genome Sciences and Policy have revealed the hidden properties of an on-off switch that governs cell growth.

The Duke team proved that if the switch is on, then a cell will divide, even if its damaged or the signal to grow disappears. Showing how the switch works may provide clues to novel drug targets for cancer and other diseases in which cell growth goes awry.

The switch is part of a critical pathway that controls cell division, the process by which the body makes new cells. Before a cell starts to divide, it goes through a checklist to make sure everything is in order, much like preparing for a long trip. If a cell senses something is wrong early on, it can halt the process. But once a cell passes a milestone called the restriction point, theres no turning back, no matter the consequences. The switch controls this milestone and is key to cell growth.

The results will appear in the April issue of the journal Nature Cell Biology. The study was funded by the National Institutes of Health, the National Science Foundation and a David and Lucile Packard Fellowship.

The switch is part of the Rb-E2F signaling pathway. Rb, or retinoblastoma, is a key tumor suppressor gene, and E2F is a transcription factor that governs the expression of all the genes important for cells to grow.

The wiring diagram is fundamentally the same. Its very likely that different organisms have evolved a very conserved design principle to regulate their growth, said Guang Yao, Ph.D., lead study author and a postdoctoral fellow in Dukes department of molecular genetics and microbiology.

The cellular pathway that includes the switch is found in all multi-cellular life, from plants to people. A cell decides to trigger the pathway when it receives an external chemical signal to grow.

During the project, the researchers discovered the switch has an unexpected property: it is b
'/>"/>