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TXK
Non-receptor tyrosine kinase that plays a redundant role with ITK 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 TXK to the cell membrane, where it is phosphorylated at Tyr-420. Phosphorylation leads to TXK full activation. Contributes also to signaling from many receptors and participates in multiple downstream pathways, including regulation of the actin cytoskeleton. Like ITK, can phosphorylate PLCG1, leading to its localization in lipid rafts and activation, followed by 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. With PARP1 and EEF1A1, TXK forms a complex that acts as a T-helper 1 (Th1) cell-specific transcription factor and binds the promoter of IFNG to directly regulate its transcription, and is thus involved importantly in Th1 cytokine production. Phosphorylates both PARP1 and EEF1A1. Phosphorylates also key sites in LCP2 leading to the up-regulation of Th1 preferred cytokine IL-2. Phosphorylates 'Tyr-201' of CTLA4 which leads to the association of PI-3 kinase with the CTLA4 receptor. Belongs to the protein kinase superfamily. Tyr protein kinase family. TEC subfamily. Expressed in T-cells and some myeloid cell lines. Expressed in Th1/Th0 cells with IFN-gamma-producing potential. Note: This description may include information from UniProtKB.
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| Protein type: EC 2.7.10.2; Kinase, protein; Protein kinase, TK; Protein kinase, tyrosine (non-receptor); TK group; Tec family |
| Chromosomal Location of human Ortholog: 4p12 |
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Cellular Component:
cytoplasm; cytosol; nucleolus; nucleoplasm; nucleus; plasma membrane
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Molecular Function:
ATP binding; non-membrane spanning protein tyrosine kinase activity; protein binding
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Biological Process:
activation of phospholipase C activity; adaptive immune response; integrin-mediated signaling pathway; positive regulation of cytokine production; positive regulation of transcription by RNA polymerase II; positive regulation of type II interferon production; positive regulation of type II interferon-mediated signaling pathway; protein autophosphorylation; protein phosphorylation; regulation of gene expression; regulation of platelet activation; T cell receptor signaling pathway; tissue regeneration
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Reference #:
P42681
(UniProtKB)
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Alt. Names/Synonyms: BTKL; MGC22473; Protein-tyrosine kinase 4; PSCTK5; PTK4; PTK4 protein tyrosine kinase 4; Resting lymphocyte kinase; RLK; TKL; TXK; TXK tyrosine kinase; tyrosine kinase; Tyrosine-protein kinase TXK
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Gene Symbols: TXK
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Molecular weight:
61,258 Da
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Basal Isoelectric point:
8.23
Predict pI for various phosphorylation states
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CST Pathways:
Tyrosine Kinases & Substrates
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