We have discovered a novel proline-driven conformational switch in the immunological protein kinase Interleukin-2 tyrosine kinase (Itk). Proline cis/trans isomerization within the Itk Src homology 2 (SH2) domain mediates conformer-specific recognition of Itk signaling partners and an important regulatory interaction with the ubiquitous peptidyl-prolyl isomerase cyclophilin A (CypA). This proposal is focused on clearly defining the role of proline isomerization in the Itk regulatory apparatus. Our extensive experience in working with Itk and CypA both at the structural and functional level places us in an ideal position to dissect the Itk regulatory mechanism. Proline isomerization is an intrinsic conformational exchange event that is most easily studied by NMR spectroscopy. Thus, our approach is anchored in structural studies that provide the indispensable atomic-level information required to fully examine the functions of these intracellular signaling proteins in T cells. Our structural insights have already been tested in mouse model systems providing further evidence that Itk regulation is linked to a single proline residue that is the target of CypA. Moreover, the proline isomerization event within Itk may represent another form of posttranslational 'modification' akin to protein phosphorylation. Like phosphorylated amino acid side chains, critical proline residues could control ligand binding and serve as recognition sites for regulatory partners such as the peptidyl-prolyl isomerases. Our detailed analysis of Itk and CypA will lay the groundwork for identification of other proline switches within the proteins that control immune cell signaling. ? ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI043957-10
Application #
7393129
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Mallia, Conrad M
Project Start
1999-01-15
Project End
2009-04-30
Budget Start
2008-03-01
Budget End
2009-04-30
Support Year
10
Fiscal Year
2008
Total Cost
$300,726
Indirect Cost
Name
Iowa State University
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
005309844
City
Ames
State
IA
Country
United States
Zip Code
50011
Devkota, Sujan; Joseph, Raji E; Boyken, Scott E et al. (2017) An Autoinhibitory Role for the Pleckstrin Homology Domain of Interleukin-2-Inducible Tyrosine Kinase and Its Interplay with Canonical Phospholipid Recognition. Biochemistry 56:2938-2949
Joseph, Raji E; Wales, Thomas E; Fulton, D Bruce et al. (2017) Achieving a Graded Immune Response: BTK Adopts a Range of Active/Inactive Conformations Dictated by Multiple Interdomain Contacts. Structure 25:1481-1494.e4
Roberts, Justin M; Tarafdar, Sreya; Joseph, Raji E et al. (2016) Dynamics of the Tec-family tyrosine kinase SH3 domains. Protein Sci 25:852-64
Chopra, Nikita; Wales, Thomas E; Joseph, Raji E et al. (2016) Dynamic Allostery Mediated by a Conserved Tryptophan in the Tec Family Kinases. PLoS Comput Biol 12:e1004826
Xie, Qian; Fulton, D Bruce; Andreotti, Amy H (2015) A selective NMR probe to monitor the conformational transition from inactive to active kinase. ACS Chem Biol 10:262-8
Devkota, Sujan; Joseph, Raji E; Min, Lie et al. (2015) Scaffold Protein SLP-76 Primes PLC?1 for Activation by ITK-Mediated Phosphorylation. J Mol Biol 427:2734-47
Boyken, Scott E; Chopra, Nikita; Xie, Qian et al. (2014) A conserved isoleucine maintains the inactive state of Bruton's tyrosine kinase. J Mol Biol 426:3656-69
Wang, Xinxin; Boyken, Scott E; Hu, Jiancheng et al. (2014) Calmodulin and PI(3,4,5)P? cooperatively bind to the Itk pleckstrin homology domain to promote efficient calcium signaling and IL-17A production. Sci Signal 7:ra74
Xie, Qian; Joseph, Raji E; Fulton, D Bruce et al. (2013) Substrate recognition of PLC?1 via a specific docking surface on Itk. J Mol Biol 425:683-96
Joseph, Raji E; Kleino, Iivari; Wales, Thomas E et al. (2013) Activation loop dynamics determine the different catalytic efficiencies of B cell- and T cell-specific tec kinases. Sci Signal 6:ra76

Showing the most recent 10 out of 34 publications