Activated Cdc42 Kinase (Ack) is a cell survival signal in Drosophila melanogaster

Activated Cdc42 kinase (Ack) is a non‐receptor tyrosine kinase that is regulated by Cdc42 and implicated in various developmental processes. Mammalian Ack has been shown to be essential for the growth of Ras transformed cells. Activated Ras has been identified in over a third of human cancers, thus we investigated Ack's influence on survival to determine if Ack can serve as a therapeutic target to treat cancer. We have identified a novel role for Ack in the regulation of programmed cell death (PCD) in D. melanogaster. Genetic interaction studies using the fly eye as an experimental system demonstrate an interaction between Ack and the death‐inducing activity of Head Involution Defective (hid). Using the hid induced small eye as a baseline, we determined that Ack influences cell survival through an uncharacterized pathway. This pathway is dependent on Ack's kinase activity, functions with the transcriptional co‐activator Yorkie and is independent of epidermal growth factor receptor (EGFR) signaling. Overall, our data suggest that Ack promotes cell survival through a novel pathway that has potential therapeutic value for the treatment of cancers containing deregulated Ras.