Tyrosine-protein kinase TXK (TXK) (TXK)

Tyrosine-protein kinase TXK, also known as Resting Lymphocyte Kinase (RLK), is a member of the TEC family of non-receptor tyrosine kinases primarily expressed in T-cells, natural killer (NK) cells, and mast cells [1, 17]. It plays a pivotal role in the adaptive immune response by regulating the development, activation, and differentiation of T-cells, particularly favoring the Th1 phenotype [7, 15]. Upon T-cell receptor (TCR) engagement, TXK is recruited to the cell membrane and activated through phosphorylation by Src family kinases, leading to the activation of phospholipase C-gamma 1 (PLC-gamma 1) and subsequent calcium mobilization [7, 8]. Additionally, TXK can translocate to the nucleus where it acts as a Th1-specific transcription factor, directly promoting the transcription of the interferon-gamma (IFNG) gene [6, 7]. Given its central role in Th1-mediated inflammatory pathways, TXK is a significant therapeutic target for autoimmune disorders such as psoriasis, rheumatoid arthritis, and inflammatory bowel disease, as well as T-cell malignancies [10, 11, 17]. Pharmacological inhibition of TXK, often in conjunction with the related kinase ITK, aims to modulate aberrant T-cell responses [11, 17]. However, therapeutic development must manage potential safety concerns like cardiovascular toxicity and off-target effects associated with TEC family inhibitors [11, 18]. Current research focuses on developing selective covalent inhibitors to minimize these risks while maintaining efficacy in treating chronic inflammatory conditions [10, 11].

Other names

Resting lymphocyte kinaseRLKBTK-like kinaseBTKLProtein-tyrosine kinase 4PTK4PSCTK5TKLPTK-RL-18

Inhibition of kinase activity by binding to the ATP-binding site, often through covalent modification of conserved cysteine residues.