Signaling molecules have pleiotropic functions and are activated by various extracellular stimuli. Protein kinase C (PKC) is activated by diverse receptors, and its dysregulation is associated with diseases including cancer. However, how the undesired activation of PKC is prevented during development remains poorly understood. We have previously shown that a protein kinase, IKKϵ, is active at the growing bristle tip and regulates actin bundle organization during Drosophila bristle morphogenesis. Here we demonstrate that IKKϵ regulates the actin bundle localization of a dynamic actin cross-linker, Fascin. IKKϵ inhibits PKC, thereby protecting Fascin from its inhibitory phosphorylation. Excess PKC activation is responsible for the actin bundle defects in ikkϵ-deficient bristles, whereas PKC is dispensable for bristle morphogenesis in wildtype bristles, indicating that PKC is repressed by IKKϵ in wildtype bristle cells. These results suggest that IKKϵ prevents excess activation of PKC during bristle morphogenesis.
- Received April 8, 2016.
- Accepted August 23, 2016.