Promiscuous Ras turns on the wrong partner

The small GTPase Ras is stimulated by epidermal growth factor receptors in flies and vertebrates. Activated Ras initiates multiple cellular responses, including cell growth and differentiation. The importance of downstream effectors such as PI3K and Myc for each response has not been firmly determined, in part because their involvement varies depending on the cell culture system used.Prober and Edgar put some of this controversy to rest by examining how Ras can control cell growth in vivo. In the developing fly wing, both Myc and PI3K were up-regulated in clones of cells expressing an activated form of Ras, which increases...