A Conserved Motif in the ITK PH-Domain Is Required for Phosphoinositide Binding and TCR Signaling but Dispensable for Adaptor Protein Interactions
| Autor: | Roman M. Levytskyy, David M. Guimond, Stephanie Rigaud, Constantine D. Tsoukas, Tomasz Zal, Nupura Hirve, Karsten Sauer |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Polyphosphoinositide Signaling Cascade
T-Lymphocytes Amino Acid Motifs lcsh:Medicine Plasma protein binding Jurkat Cells Mice 0302 clinical medicine Phosphatidylinositol Phosphates Molecular Cell Biology Signaling in Cellular Processes Membrane Receptor Signaling Phosphorylation lcsh:Science Immune Response Conserved Sequence 0303 health sciences Multidisciplinary T Cells Kinase Mechanisms of Signal Transduction Signal transducing adaptor protein Signaling in Selected Disciplines Protein-Tyrosine Kinases Signaling Cascades Cell biology Pleckstrin homology domain Biochemistry Lipid Signaling Medicine Signal transduction Immunologic Receptor Signaling Tyrosine kinase Research Article Signal Transduction Protein Binding Immune Cells Immunology Molecular Sequence Data Receptors Antigen T-Cell Phosphoinositide Signal Transduction Biology Immunological Signaling Transfection Signaling Pathways Immune Activation Structure-Activity Relationship 03 medical and health sciences Animals Humans Amino Acid Sequence Adaptor Proteins Signal Transducing 030304 developmental biology Cell Nucleus Binding Sites Phospholipase C gamma lcsh:R TCR signalosome Immunity Immunoregulation Protein Structure Tertiary HEK293 Cells Phospholipid Signaling Cascade Clinical Immunology Mutant Proteins lcsh:Q Interleukin-4 030215 immunology |
| Zdroj: | PLoS ONE, Vol 7, Iss 9, p e45158 (2012) PLoS ONE |
| ISSN: | 1932-6203 |
| DOI: | 10.1371/journal.pone.0045158 |
| Popis: | Binding of the membrane phospholipid phosphatidylinositol 3,4,5-trisphosphate (PIP(3)) to the Pleckstrin Homology (PH) domain of the Tec family protein tyrosine kinase, Inducible T cell Kinase (ITK), is critical for the recruitment of the kinase to the plasma membrane and its co-localization with the TCR-CD3 molecular complex. Three aromatic residues, termed the FYF motif, located in the inner walls of the phospholipid-binding pocket of the ITK PH domain, are conserved in the PH domains of all Tec kinases, but not in other PH-domain containing proteins, suggesting an important function of the FYF motif in the Tec kinase family. However, the biological significance of the FYF amino acid motif in the ITK-PH domain is unknown. To elucidate it, we have tested the effects of a FYF triple mutant (F26S, Y90F, F92S), henceforth termed FYF-ITK mutant, on ITK function. We found that FYF triple mutation inhibits the TCR-induced production of IL-4 by impairing ITK binding to PIP(3), reducing ITK membrane recruitment, inducing conformational changes at the T cell-APC contact site, and compromising phosphorylation of ITK and subsequent phosphorylation of PLCγ(1). Interestingly, however, the FYF motif is dispensable for the interaction of ITK with two of its signaling partners, SLP-76 and LAT. Thus, the FYF mutation uncouples PIP(3)-mediated ITK membrane recruitment from the interactions of the kinase with key components of the TCR signalosome and abrogates ITK function in T cells. |
| Databáze: | OpenAIRE |
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