Tyrosine-protein kinase ITK/TSK - Q08881 (ITK_HUMAN)

 

Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for Q08881: 35
 
Function
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. UniProt
Catalytic Activity
ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. UniProt
Pathway Maps
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      ESCHER  BiGG
Subunit Structure
Homooligomerizes; this association negatively regulates kinase activity (By similarity). Interacts with PPIA/CYPA; this interaction regulates TCR signal strength via a proline-directed conformational switch in ITK. Interacts with THEMIS (By similarity). Interacts with FASLG. Interacts with VAV1; this interaction is important for VAV1 localization and TCR-induced actin polarization. UniProt
Domain
The N-terminal PH domain allows ITK to be recruited to the plasma membrane by an activated PI3 kinase. This domain contains also a proline-rich region (PRR). The adjoining domain is a SH3 domain, which binds to PRR (from itself or from other proteins). Next, a SH2 domain is required for binding tyrosine-phosphorylated substrates. In the C-terminal region, the kinase domain is required for tyrosine phosphorylation. UniProt
This protein in other organisms (by gene name):
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Data in green originates from UniProtKB  
Variation data (sourced from UniProt) shows non-genetic variation from the ExPASy   and dbSNP   websites.
Data in yellow originates from Pfam  , by interacting with the HMMER3 web site  
Data in purple originates from Phosphosite  .
Data in orange originates from the SCOP   (version 1.75) and SCOPe   (version 2.04) classifications.
Data in grey has been calculated using BioJava  . Protein disorder predictions are based on JRONN (Troshin, P. and Barton, G. J. unpublished), a Java implementation of RONN  
  • Red: potentially disorderd region
  • Blue: probably ordered region.
Hydropathy has been calculated using a sliding window of 15 residues and summing up scores from standard hydrophobicity tables.
  • Red: hydrophobic
  • Blue: hydrophilic.
Data in lilac represent the genomic exon structure projected onto the UniProt sequence.
Data in blue originates from PDB
  • Secstruc: Secondary structure projected from representative PDB entries onto the UniProt sequence.
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Validation Track

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Data in red indicates combined ranges of Homology Models from SBKB   and the Protein Model Portal  
The PDB to UniProt mapping is based on the data provided by the EBI SIFTS project. See also Velankar et al., Nucleic Acids Research 33, D262-265 (2005).
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