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Proc Natl Acad Sci U S A. 2019 Oct 7. pii: 201907566. doi: 10.1073/pnas.1907566116. [Epub ahead of print]

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

Author information

1
Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011.
2
Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115.
3
Institute of Bioinformatics and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602.
4
Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011; amyand@iastate.edu.

Abstract

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

PMID:
31591208
DOI:
10.1073/pnas.1907566116
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Conflict of interest statement

Competing interest statement: A.H.A. has an equity interest in ImmVue Therapeutics, Inc., a company that may potentially benefit from the research results. The terms of this arrangement have been reviewed and approved by Iowa State University in accordance with its conflict of interest policies.

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