VPS26A and brain neoplasm: While expression of either vps26-RNAi or Su(dx)-C917A, a dominant negative form of Su(dx) (Su(dx)-DN) that lacks its E3 ubiquitin ligase activity (Wang et al., 2015), by PntP1-Gal4, led to a mild neuroblast overproliferation phenotype (Figure 6C,D), simultaneous expression of vps26-RNAi and Su(dx)-DN resulted in a severe brain tumor phenotype (Figure 6C,D).