Details of the Drug Therapeutic Target (DTT)

General Information of Drug Therapeutic Target (DTT) (ID: TT8M1DP)

• DTT Name: Tyrosine-protein kinase TXK (TXK)
• Synonyms: Resting lymphocyte kinase; RLK; Protein-tyrosine kinase 4; PTK4
• Gene Name: TXK
• DTT Type: Literature-reported target; [1]
• UniProt ID: TXK_HUMAN
• TTD ID: T32590
• EC Number: EC 2.7.10.2
• Sequence:
  MILSSYNTIQSVFCCCCCCSVQKRQMRTQISLSTDEELPEKYTQRRRPWLSQLSNKKQSN
  TGRVQPSKRKPLPPLPPSEVAEEKIQVKALYDFLPREPCNLALRRAEEYLILEKYNPHWW
  KARDRLGNEGLIPSNYVTENKITNLEIYEWYHRNITRNQAEHLLRQESKEGAFIVRDSRH
  LGSYTISVFMGARRSTEAAIKHYQIKKNDSGQWYVAERHAFQSIPELIWYHQHNAAGLMT
  RLRYPVGLMGSCLPATAGFSYEKWEIDPSELAFIKEIGSGQFGVVHLGEWRSHIQVAIKA
  INEGSMSEEDFIEEAKVMMKLSHSKLVQLYGVCIQRKPLYIVTEFMENGCLLNYLRENKG
  KLRKEMLLSVCQDICEGMEYLERNGYIHRDLAARNCLVSSTCIVKISDFGMTRYVLDDEY
  VSSFGAKFPIKWSPPEVFLFNKYSSKSDVWSFGVLMWEVFTEGKMPFENKSNLQVVEAIS
  EGFRLYRPHLAPMSIYEVMYSCWHEKPEGRPTFAELLRAVTEIAETW
• Function: 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.
• Reactome Pathway: FCERI mediated Ca+2 mobilization (R-HSA-2871809)

Molecular Interaction Atlas (MIA) of This DTT

3 Investigative Drug(s) Targeting This DTT

Drug Name	Drug ID	Indication	ICD 11	Highest Status	REF
PMID17600705C23	DMJFOGW	Discovery agent	N.A.	Investigative	[1]
PMID24915291C31	DMN7QB8	Discovery agent	N.A.	Investigative	[2]
PMID24915291C38	DMBXT9J	Discovery agent	N.A.	Investigative	[2]

References

• [1] N-4-Pyrimidinyl-1H-indazol-4-amine inhibitors of Lck: indazoles as phenol isosteres with improved pharmacokinetics. Bioorg Med Chem Lett. 2007 Aug 1;17(15):4363-8.
• [2] Discovery of a series of 2,5-diaminopyrimidine covalent irreversible inhibitors of Bruton's tyrosine kinase with in vivo antitumor activity. J Med Chem. 2014 Jun 26;57(12):5112-28.