TXK siRNA (Human)

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 cytoskekleton. 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.

Protein type: EC 2.7.10.2; Protein kinase, tyrosine (non-receptor); Kinase, protein; Protein kinase, TK; TK group; Tec family

Chromosomal Location of Human Ortholog: 4p12

Cellular Component: extrinsic to internal side of plasma membrane; cytoplasm; nucleus

Molecular Function: protein binding; non-membrane spanning protein tyrosine kinase activity; ATP binding; receptor binding

Biological Process: adaptive immune response; transcription, DNA-dependent; protein amino acid autophosphorylation; cytokine production; T cell receptor signaling pathway; protein amino acid phosphorylation; regulation of cell proliferation; regulation of transcription from RNA polymerase II promoter; positive regulation of interferon-gamma production; interleukin-4 production; B cell receptor signaling pathway; phospholipase C activation; interferon-gamma production; positive regulation of transcription from RNA polymerase II promoter; NK T cell differentiation; transmembrane receptor protein tyrosine kinase signaling pathway; T cell differentiation