Haire R N, Ohta Y, Lewis J E, Fu S M, Kroisel P, Litman G W
Department of Pediatrics, University of South Florida, All Children's Hospital, St Petersburg 33701.
Hum Mol Genet. 1994 Jun;3(6):897-901. doi: 10.1093/hmg/3.6.897.
A gene for a novel, putative cytoplasmic tyrosine kinase, TXK has been isolated from a human peripheral blood cDNA library. The complete nucleotide sequence of the cDNA indicates that it is related most closely to EMT, a tyrosine kinase of T cells and to the B-cell tyrosine kinase Btk, which is mutated in X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency disease (XID) in mouse. TXK, like BTK, is a member of the Tec sub-family of Src-type (non-receptor) tyrosine kinases. Like similar Tec sub-family members, and unlike the other Src kinases, TXK lacks both the N-terminal myristylation signal and the C-terminal regulatory tyrosine. TXK expression is detected primarily in T cells and some myeloid cell lines but not in a number of other cell types. TXK shares 60% amino acid homology with EMT and 57% with BTK over the SH3, SH2 (Src-homology) and catalytic domains but unlike BTK, EMT and tec, it lacks Gap 1 homology and steroid hormone receptor homology in the N-terminal region. Genomic clones containing TXK have been isolated and hybridize to chromosome position 4p12.
从人外周血cDNA文库中分离出一种编码新型假定细胞质酪氨酸激酶TXK的基因。该cDNA的完整核苷酸序列表明，它与T细胞酪氨酸激酶EMT以及B细胞酪氨酸激酶Btk关系最为密切，Btk在人类的X连锁无丙种球蛋白血症（XLA）和小鼠的X连锁免疫缺陷病（XID）中发生突变。与BTK一样，TXK是Src型（非受体）酪氨酸激酶Tec亚家族的成员。与类似的Tec亚家族成员一样，与其他Src激酶不同，TXK既缺乏N端肉豆蔻酰化信号，也缺乏C端调节酪氨酸。TXK表达主要在T细胞和一些髓系细胞系中检测到，但在许多其他细胞类型中未检测到。TXK在SH3、SH2（Src同源）和催化结构域与EMT有60%的氨基酸同源性，与BTK有57%的氨基酸同源性，但与BTK、EMT和tec不同，它在N端区域缺乏Gap 1同源性和类固醇激素受体同源性。已分离出含有TXK的基因组克隆，并与染色体位置4p12杂交。
