August 2005

Insight into JAK/STAT

Dr. Norbert Perrimon and colleagues at Harvard Medical School (Boston, MA) have used a genome-wide RNAi screen in cultured Drosophila cells to identify novel regulators of the JAK/STAT signaling pathway. In a stunning example of the utility of cell-based RNAi analysis in a genetically tractable system, like fruit flies, the researchers identified 121 genes involved in the JAK/STAT pathway, including a key, and previously unidentified, negative regulator of the pathway. PTP61F emerged from the screen as the first protein tyrosine phosphatase to inhibit JAK/STAT signaling. Since the JAK/STAT pathway is conserved between insects and mammals, the authors speculate that many of the new genes that they have identified will turn out to be important to understanding the role of this pathway in both human immune disorders and tumorigenesis.