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在白细胞介素２（ｉｎｔｅｒｌｅｕｋｉｎ２ ，ＩＬ２）的信号转导过程中， 酪氨酸激酶Ｊａｋ３ 起着至关重要的作用。它不但参与ＪａｋＳｔａｔ 通路的传递， 而且通过与一些未知的信号分子相互作用调节一些原癌基因的表达， 如ｃｆｏｓ，ｃｍｙｃ等。由于目前越来越多的证据表明在信号转导过程中两个蛋白质之间的相互作用需要磷酸酪氨酸的存在， 为此构建了酪氨酸磷酸化相关的酵母双杂交系统， 以进一步阐释Ｊａｋ３ 在ＩＬ２ 信号通路中的作用。利用这个系统， 以Ｊａｋ３ 的Ｎ 端ＪＨ３ ～ＪＨ７ 区域筛选外周血白细胞ｃＤＮＡ库。结果得到了５０ 多个双阳性克隆。测序结果表明其中一个为核小体组装蛋白１（Ｎａｐ１） 的基因， 它编码３９２ 个氨基酸残基。实验还证明Ｎａｐ１ 与Ｊａｋ３ 之间的相互作用在一定程度上依赖于酪氨酸磷酸化。用免疫共沉淀及蛋白质印迹实验证明在小鼠原Ｂ淋巴细胞株ＢＡＦ／ＢＯ３β细胞中确实存在着核小体组装蛋白Ｎａｐ１ 与酪氨酸激酶Ｊａｋ３ Ｎ 端的相互作用。
In the interleukin 2 (IL 2) signal transduction, tyrosine kinase Jak3 plays a crucial role. It not only participates in the transmission of Jak-Stat pathway, but also regulates the expression of some proto-oncogenes by interacting with some unknown signal molecules, such as c-fos, c-myc and so on. As more and more evidences show that the interaction between two proteins requires the presence of phosphotyrosine during signal transduction, a yeast two-hybrid system involving tyrosine phosphorylation has been constructed for further elucidation Jak3 role in the IL 2 signaling pathway. Using this system, the peripheral blood leukocyte cDNA library was screened from the N-terminal JH3 ~ JH7 region of Jak3. As a result, more than 50 double positive clones were obtained. Sequencing results showed that one of them was nucleosome assembly protein 1 (Nap1), encoding 392 amino acid residues. Experiments also show that the interaction between Nap1 and Jak3 depends to some extent on tyrosine phosphorylation. Co-immunoprecipitation and Western blotting demonstrated that there was indeed an interaction between the nucleosome assembly protein Nap1 and the tyrosine kinase Jak3 N-terminal in the murine B lymphoblastoid cell line BAF / BO3β.