Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states

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-ric...

Full description

Saved in:
Bibliographic Details
Published in:eLife 2024-01, Vol.12
Main Authors: Lin, David Yin-Wei, Kueffer, Lauren E, Juneja, Puneet, Wales, Thomas E, Engen, John R, Andreotti, Amy H
Format: Article
Language:English
Subjects:
Agammaglobulinaemia Tyrosine Kinase
Allosteric properties
Bruton's tyrosine kinase
BTK
conformational states
Cryoelectron Microscopy
Crystal structure
Crystallography
Crystals
Dimerization
Electron microscopy
Homology
kinase regulation
kinase structure
Kinases
Life Sciences & Biomedicine - Other Topics
Mutation
NMR
Nuclear magnetic resonance
Phosphatidylinositol
Phosphorylation
Pleckstrin
Protein Domains
Structural Biology and Molecular Biophysics
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:2050-084X
2050-084X
DOI:10.7554/eLife.89489