The non-receptor tyrosine kinase Abelson (Abl) is a key player in oncogenesis, causing diseases including chronic myelogenous and acute lymphoblastic leukemia. Drugs targeting Abl kinase activity serve as paradigms of targeted therapy. Drosophila is an ideal model for studying Abl’s function because there is only a single fly Abl family member. In flies, Abl is essential for embryonic morphogenesis, playing diverse roles in embryonic and adult viability. To examine the role of the intrinsically disordered region (IDR) of Abl, researchers deleted the IDR in Drosophila. They found that Abl lacking the IDR was not able to rescue the roles of Abl in viability and embryonic morphogenesis. The IDR was also essential for cell shape changes and cytoskeletal regulation during embryonic morphogenesis and, surprisingly, for modulating protein stability. These data provide insight into the role of the IDR as an important signaling component in Abl and suggest that IDRs may play diverse roles in a broad variety of signaling proteins.