Crystal structure of the c-abl kinase domain (cyan) in complex with imatinib (Gleevec) (colored orange). Imatinib is specific for the TK domain in abl (the Abelson proto-oncogene), c-kit and PDGF-R (platelet-derived growth factor receptor). Imatinib (Gleevec) blocks the activity of Abelson cytoplasmic tyrosine kinase (ABL), c-Kit and the platelet-derived growth factor receptor (PDGFR). As an inhibitor of PDGFR, imatinib mesylate appears to have utility in the treatment of a variety of dermatological diseases. Imatinib has been reported to be an effective treatment for FIP1L1-PDGFRalpha+ mast cell disease, hypereosinophilic syndrome, and dermatofibrosarcoma protuberans. Model based on Protein Database entry 1IEP.