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NMR Structure of the Itk SH2 domain, Pro287trans, energy minimized average structure
Structural highlights
FunctionITK_MOUSE Tyrosine kinase that plays an essential role in regulation of the adaptive immune response. Regulates the development, function and differentiation of conventional T-cells and nonconventional NKT-cells. When antigen presenting cells (APC) activate T-cell receptor (TCR), a series of phosphorylation lead to the recruitment of ITK to the cell membrane, in the vicinity of the stimulated TCR receptor, where it is phosphorylated by LCK. Phosphorylation leads to ITK autophosphorylation and full activation. Once activated, phosphorylates PLCG1, leading to the activation of this lipase and subsequent cleavage of its substrates. In turn, the endoplasmic reticulum releases calcium in the cytoplasm and the nuclear activator of activated T-cells (NFAT) translocates into the nucleus to perform its transcriptional duty. Phosphorylates 2 essential adapter proteins: the linker for activation of T-cells/LAT protein and LCP2. Then, a large number of signaling molecules such as VAV1 are recruited and ultimately lead to lymphokine production, T-cell proliferation and differentiation.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedInterleukin-2 tyrosine kinase (Itk) is a T cell-specific kinase required for a proper immune response following T cell receptor engagement. In addition to the kinase domain, Itk is composed of several noncatalytic regulatory domains, including a Src homology 2 (SH2) domain that contains a conformationally heterogeneous Pro residue. Cis-trans isomerization of a single prolyl imide bond within the SH2 domain mediates conformer-specific ligand recognition that may have functional implications in T cell signaling. To better understand the mechanism by which a proline switch regulates ligand binding, we have used NMR spectroscopy to determine two structures of Itk SH2 corresponding to the cis and trans imide bond-containing conformers. The structures indicate that the heterogeneous Pro residue acts as a hinge that modulates ligand recognition by controlling the relative orientation of protein-binding surfaces. Structural characterization of a proline-driven conformational switch within the Itk SH2 domain.,Mallis RJ, Brazin KN, Fulton DB, Andreotti AH Nat Struct Biol. 2002 Dec;9(12):900-5. PMID:12402030[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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