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Title | Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states. |
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Journal, issue, pages | Elife, Vol. 12, Year 2024 |
Publish date | Jan 8, 2024 |
Authors | David Yin-Wei Lin / Lauren E Kueffer / Puneet Juneja / Thomas E Wales / John R Engen / Amy H Andreotti / |
PubMed Abstract | Full-length Bruton's tyrosine kinase (BTK) has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely ...Full-length Bruton's tyrosine kinase (BTK) has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology [PHTH] domain and proline-rich regions [PRR] contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveal only the SH3-SH2-kinase core with no electron density visible for the PHTH-PRR segment. Cryo-electron microscopy (cryoEM) data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH-PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3-SH2-kinase core. On the way to activation, disassembly of the SH3-SH2-kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with phosphatidylinositol (3,4,5)-trisphosphate. Membrane-induced dimerization activates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to trans-autophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation. |
External links | Elife / PubMed:38189455 / PubMed Central |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 2.1 - 6.36 Å |
Structure data | EMDB-40585: CryoEM reconstruction of full-length Btk (class 0) EMDB-40586: CryoEM reconstruction of full-length Btk (class 1) EMDB-40587: CryoEM reconstruction of full-length Btk (class 3) PDB-8gmb: PDB-8s93: PDB-8s9f: |
Chemicals | ChemComp-9AJ: ChemComp-ZN: ChemComp-GOL: ChemComp-HOH: ChemComp-1N1: |
Source |
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Keywords | TRANSFERASE / ATP-binding / Lipid-binding / transcription regulation / immunity / Bruton's tyrosine kinase / Non-receptor tyrosine kinase / complex / protein phosphorylation |