John Sedivy and Kam Yeung have discovered a new mechanism of mammalian cell division, signaled by a molecule called Raf kinase inhibitor protein (RKIP). RKIP represents a powerful weapon against cancerous cells.
Most cancer research attempts to explain how a cell divides. Although researchers have a general understanding of the process, many intricate mechanisms of cell division are just now being discovered.
Recently, two Brown professors provided one more piece of this puzzle. John Sedivy and Kam Yeung of the Department of Molecular Biology, Cell Biology and Biochemistry discovered a new mechanism of mammalian cell division - signaled by a molecule called Raf kinase inhibitor protein (RKIP). RKIP represents a powerful weapon against cancerous cells because at high intracellular levels, it prevents a cell from dividing, and thus cancer from growing. The research was published in the Sept. 9 issue of Nature.
The discovery of RKIP's function significantly advances the knowledge about signal transduction - how a cell perceives a stimulus and responds appropriately. "This mechanism is a major drug target," Sedivey said. "If you want to design a drug, you want to know as much as possible about the mechanism."
Because scientists do not completely understand the signal transduction mechanism, good drug targets are rare. The discovery of RKIP's function represents a much-needed new target.
In 1993, Sedivy made the initial discovery of RKIP. Subsequently he found that RKIP physically binds to an enzyme and blocks it from signaling the cell to divide. When the RKIP intracellular level passes a certain threshold, cell proliferation is inhibited, he said. But if cancer is caused by a mutation after this binding and blocking process, then the cell will continue to receive the signal and divide. Therefore drugs that target RKIP would only be successful in stopping unregulated cell division under certain circumstances.
"Although we now understand the mechanism by which RKIP regulates proliferation, we still do not know how the cell modulates the level of RKIP," Sedivy said. "Answering that is the next step in this research and it may bring us one step closer to a new drug for cancer."
Amita Kulkarni '00 is concentrating in international relations.