Azam Mohammad, Seeliger Markus A, Gray Nathanael S, Kuriyan John, Daley George Q
Karp research building, 7th floor, Division of Pediatric Hematology/Oncology, Children's Hospital of Boston, Massachusetts 02115, USA.
Nat Struct Mol Biol. 2008 Oct;15(10):1109-18. doi: 10.1038/nsmb.1486. Epub 2008 Sep 14.
Protein kinases targeted by small-molecule inhibitors develop resistance through mutation of the 'gatekeeper' threonine residue of the active site. Here we show that the gatekeeper mutation in the cellular forms of c-ABL, c-SRC, platelet-derived growth factor receptor-alpha and -beta, and epidermal growth factor receptor activates the kinase and promotes malignant transformation of BaF3 cells. Structural analysis reveals that a network of hydrophobic interactions-the hydrophobic spine-characteristic of the active kinase conformation is stabilized by the gatekeeper substitution. Substitution of glycine for the residues constituting the spine disrupts the hydrophobic connectivity and inactivates the kinase. Furthermore, a small-molecule inhibitor that maximizes complementarity with the dismantled spine (compound 14) inhibits the gatekeeper mutation of BCR-ABL-T315I. These results demonstrate that mutation of the gatekeeper threonine is a common mechanism of activation for tyrosine kinases and provide structural insights to guide the development of next-generation inhibitors.
被小分子抑制剂靶向的蛋白激酶通过活性位点“守门人”苏氨酸残基的突变产生耐药性。在此我们表明，c-ABL、c-SRC、血小板衍生生长因子受体α和β以及表皮生长因子受体的细胞形式中的守门人突变激活了激酶，并促进了BaF3细胞的恶性转化。结构分析表明，活性激酶构象所特有的疏水相互作用网络——疏水脊柱——通过守门人取代得以稳定。用甘氨酸取代构成脊柱的残基会破坏疏水连接性并使激酶失活。此外，一种与拆解后的脊柱具有最大互补性的小分子抑制剂（化合物14）可抑制BCR-ABL-T315I的守门人突变。这些结果表明，守门人苏氨酸的突变是酪氨酸激酶激活的常见机制，并为指导下一代抑制剂的开发提供了结构上的见解。
