Lipid-targeting pleckstrin homology domain turns its autoinhibitory face toward the TEC kinases

Proc Natl Acad Sci U S A. 2019 Oct 22;116(43):21539-21544. doi: 10.1073/pnas.1907566116. Epub 2019 Oct 7.


The pleckstrin homology (PH) domain is well known for its phospholipid targeting function. The PH-TEC homology (PHTH) domain within the TEC family of tyrosine kinases is also a crucial component of the autoinhibitory apparatus. The autoinhibitory surface on the PHTH domain has been previously defined, and biochemical investigations have shown that PHTH-mediated inhibition is mutually exclusive with phosphatidylinositol binding. Here we use hydrogen/deuterium exchange mass spectrometry, nuclear magnetic resonance (NMR), and evolutionary sequence comparisons to map where and how the PHTH domain affects the Bruton's tyrosine kinase (BTK) domain. The data map a PHTH-binding site on the activation loop face of the kinase C lobe, suggesting that the PHTH domain masks the activation loop and the substrate-docking site. Moreover, localized NMR spectral changes are observed for non-surface-exposed residues in the active site and on the distal side of the kinase domain. These data suggest that the association of PHTH induces allosteric conformational shifts in regions of the kinase domain that are critical for catalysis. Through statistical comparisons of diverse tyrosine kinase sequences, we identify residues unique to BTK that coincide with the experimentally determined PHTH-binding surface on the kinase domain. Our data provide a more complete picture of the autoinhibitory conformation adopted by full-length TEC kinases, creating opportunities to target the regulatory domains to control the function of these kinases in a biological setting.

Keywords: PH domain; kinase; regulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agammaglobulinaemia Tyrosine Kinase / chemistry*
  • Agammaglobulinaemia Tyrosine Kinase / genetics
  • Agammaglobulinaemia Tyrosine Kinase / metabolism*
  • Allosteric Regulation
  • Binding Sites
  • Humans
  • Lipid Metabolism
  • Lipids / chemistry
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Pleckstrin Homology Domains
  • Protein Domains
  • Protein-Tyrosine Kinases / chemistry
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism


  • Lipids
  • Tec protein-tyrosine kinase
  • Protein-Tyrosine Kinases
  • Agammaglobulinaemia Tyrosine Kinase