Cryo-EM analyses of KIT and oncogenic mutants reveal structural oncogenic plasticity and a target for therapeutic intervention
| Autor: | Stefan G. Krimmer, Nicole Bertoletti, Yoshihisa Suzuki, Luka Katic, Jyotidarsini Mohanty, Sheng Shu, Sangwon Lee, Irit Lax, Wei Mi, Joseph Schlessinger |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | Proceedings of the National Academy of Sciences. 120 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.2300054120 |
| Popis: | The receptor tyrosine kinase KIT and its ligand stem cell factor (SCF) are required for the development of hematopoietic stem cells, germ cells, and other cells. A variety of human cancers, such as acute myeloid leukemia, gastrointestinal stromal tumor, and mast cell leukemia, are driven by somatic gain-of-function KIT mutations. Here, we report cryo electron microscopy (cryo-EM) structural analyses of full-length wild-type and two oncogenic KIT mutants, which show that the overall symmetric arrangement of the extracellular domain of ligand-occupied KIT dimers contains asymmetric D5 homotypic contacts juxtaposing the plasma membrane. Mutational analysis of KIT reveals in D5 region an “Achilles heel” for therapeutic intervention. A ligand-sensitized oncogenic KIT mutant exhibits a more comprehensive and stable D5 asymmetric conformation. A constitutively active ligand-independent oncogenic KIT mutant adopts a V-shaped conformation solely held by D5-mediated contacts. Binding of SCF to this mutant fully restores the conformation of wild-type KIT dimers, including the formation of salt bridges responsible for D4 homotypic contacts and other hallmarks of SCF-induced KIT dimerization. These experiments reveal an unexpected structural plasticity of oncogenic KIT mutants and a therapeutic target in D5. |
| Databáze: | OpenAIRE |
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