- Liu X, Chen M, Lobo P, An J, Grace Cheng SW, Moradian A, Morin GB, Van Petegem F, Jiang X
- Molecular and structural characterization of the SH3 domain of AHI-1 in regulation of cellular resistance of BCR-ABL(+) chronic myeloid leukemia cells To tyrosine kinase inhibitors.
- Proteomics. 2012 May 24. doi: 10.1002/pmic.201100553.
- ABL tyrosine kinase inhibitor (TKI) therapy induces clinical remission in chronic myeloid leukemia (CML) patients but early relapses and later emergence of TKI-resistant disease remain problematic. We recently demonstrated that the AHI-1 oncogene physically interacts with BCR-ABL and JAK2 and mediates cellular resistance to TKI in CML stem/progenitor cells. We now show that deletion of the SH3 domain of AHI-1 significantly enhances apoptotic response of BCR-ABL(+) cells to TKIs compared to cells expressing full-length AHI-1. We have also discovered a novel interaction between AHI-1 and Dynamin-2, a GTPase, through the AHI-1 SH3 domain. The crystal structure of the AHI-1 SH3 domain at 1.53-A resolution reveals that it adopts canonical SH3 folding, with the exception of an unusual C-terminal alpha helix. PD1R peptide, known to interact with the PI3K SH3 domain, was used to model the binding pattern between the AHI-1 SH3 domain and its ligands. These studies showed that an "Arg-Arg-Trp" stack may form within the binding interface, providing a potential target site for designing specific drugs. The crystal structure of the AHI-1 SH3 domain thus provides a valuable tool for identification of key interaction sites in regulation of drug resistance and for the development of small molecule inhibitors for CML.