TYROSINE PHOSPHORYLATION OF P95(VAV) IN MYELOID CELLS IS REGULATED BY GM-CSF, IL-3 AND STEEL FACTOR AND IS CONSTITUTIVELY INCREASED BY P210(BCR/ABL)
TYROSINE PHOSPHORYLATION OF P95(VAV) IN MYELOID CELLS IS REGULATED BY GM-CSF, IL-3 AND STEEL FACTOR AND IS CONSTITUTIVELY INCREASED BY P210(BCR/ABL)
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DOI：
10.1002/j.1460-2075.1995.tb06999.x
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发表时间：
1995-01-16
期刊：
影响因子：
11.4
通讯作者：
GRIFFIN, JD
中科院分区：
文献类型：
--
作者：
MATSUGUCHI, T;INHORN, RC;GRIFFIN, JD
Vav是最近发现的一种仅在造血细胞中表达的原癌基因，它含有一个SH2和两个SH3结构域，与DBL、GDP-GTP交换因子和BCR有同源性。P95(Vav)在酪氨酸残基上被磷酸化，以响应T细胞抗原受体的刺激、IgE或IgM受体的交联以及Steel因子对未成熟造血细胞的刺激。制备抗人Vav的单抗，用于检测髓系细胞中调节P95酪氨酸磷酸化(Vav)的事件。在因子依赖的MO7e细胞系中，P95(Vav)被GM-CSF、IL-3和Steel因子以剂量和时间依赖的方式快速磷酸化在酪氨酸残基上。将bcr/abl癌基因导入该细胞系后，P95(Vav)酪氨酸磷酸化的非因子依赖性增殖和组成性磷酸化P95(Vav)也显著增加，用酪氨酸磷酸酶抑制剂钒酸钠处理缺乏细胞因子的细胞，由于许多已知诱导P95(Vav)酪氨酸磷酸化的细胞因子也激活JAK家族酪氨酸激酶，我们在GM-CSF刺激的MO7E细胞中寻找P95(Vav)与JAK激动酶的相互作用，P95(Vav)与JAK2共沉淀。此外，利用杆状病毒载体在昆虫细胞中高水平表达JAK2时，也发现JAK2与P95(Vav)在体内具有结构性联系。谷胱甘肽-S-转移酶与P95(Vav)SH2结构域的融合蛋白(GST-Vav-SH2)沉淀了JAK2，提示这种相互作用是由P95(Vav)的SH2结构域介导的。GST-Vav-SH2，而不是GST，也沉淀了JAK1、JAK3和TYK2，提示其他JAK家族可能与P95(Vav)相互作用。这些结果表明，P95(Vav)的酪氨酸磷酸化可能受到JAK激酶的直接调节，并进一步表明Vav广泛参与了多种细胞因子和癌基因bcr/abl启动的髓系细胞的信号转导。
Vav is a recently described proto-oncogene expressed only in hematopoietic cells which contains an SH2 and two SH3 domains and shares homology with the Dbl GDP-GTP exchange factor and BCR. p95(Vav) is phosphorylated on tyrosine residues in response to stimulation of the T cell antigen receptor, cross-linking of IgE or IgM receptors and stimulation of immature hematopoietic cells by Steel factor. Monoclonal antibodies to human Vav were generated and used to examine the events which regulate tyrosine phosphorylation of p95(Vav) in myeloid cells. In the factor-dependent MO7e cell line, p95(Vav) was rapidly phosphorylated on tyrosine residues in a dose- and time-dependent manner by GM-CSF, IL-3 and Steel factor. Introduction of the BCR/ABL oncogene into this cell line resulted in factor-independent proliferation and constitutive phosphorylation of p95(Vav) Tyrosine phosphorylation of p95(Vav) was also substantially increased by treatment of cytokine-deprived cells with the tyrosine phosphatase inhibitor sodium vanadate, Since many of the cytokines known to induce tyrosine phosphorylation of p95(Vav) are also known to activate JAK family tyrosine kinases, we looked for an interaction of p95(Vav) with JAK kinases, p95(Vav) coprecipitated with JAK2 in MO7e cells stimulated with GM-CSF, but not in unstimulated cells. Also, JAK2 was found to be constitutively associated with p95(Vav) in vivo when expressed at high levels in insect cells using baculovirus vectors. A fusion protein consisting of glutathione-S-transferase and the SH2 domain of p95(Vav) (GST-Vav-SH2) precipitated JAK2, suggesting that this interaction is mediated by the SH2 domain of p95(Vav). GST-Vav-SH2, but not GST, also precipitated JAK1, JAK3 and Tyk2, suggesting that other JAK family kinases might interact with p95(Vav). These results suggest that tyrosine phosphorylation of p95(Vav) is potentially directly regulated by JAK kinases, and further suggest that Vav is broadly involved in signal transduction in myeloid cells initiated by many cytokines and the oncogene BCR/ABL.