Ligand-independent activation of c-kit receptor tyrosine kinase in a murine mastocytoma cell line P-815 generated by a point mutation
Ligand-independent activation of c-kit receptor tyrosine kinase in a murine mastocytoma cell line P-815 generated by a point mutation
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DOI：
10.1182/blood.v83.9.2619.bloodjournal8392619
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发表时间：
1994-05
期刊：
影响因子：
20.3
通讯作者：
T. Tsujimura;T. Furitsu;M. Morimoto;K. Isozaki;S. Nomura;Y. Matsuzawa;Y. Kitamura;Y. Kanakura
中科院分区：
文献类型：
--
作者：
T. Tsujimura;T. Furitsu;M. Morimoto;K. Isozaki;S. Nomura;Y. Matsuzawa;Y. Kitamura;Y. Kanakura
c-kit 原癌基因编码一种受体酪氨酸激酶，已知该受体在造血过程中发挥着至关重要的作用，尤其是在肥大细胞的生长和分化中。尽管 c-kit 基因的许多显性功能丧失突变已在小鼠、大鼠和人类中得到了很好的表征，但我们对 c-kit 突变导致 c-kit 受体酪氨酸激酶 (KIT) 的配体非依赖性激活知之甚少。在小鼠肥大细胞瘤细胞系 P-815 中，KIT 被发现在酪氨酸上被组成型磷酸化，并以不依赖配体的方式被激活。对c-kit cDNA整个编码区的测序表明，P-815细胞的c-kit cDNA在密码子814处携带点突变，导致Tyr氨基酸替换为Asp。编码密码子814中Tyr的鼠野生型c-kit cDNA和突变型c-kit cDNA在人胚胎肾细胞系293T的细胞中表达。在转染细胞中，突变型 KITTyr814 在酪氨酸上显着磷酸化，并在免疫复合物激酶反应中被激活，无论是否受到 KIT（干细胞因子）配体的刺激，而在野生型 KIT 中几乎检测不到酪氨酸磷酸化和激活。这里提供的数据为 c-kit 基因的新型激活突变提供了证据，该突变可能参与某些细胞类型（包括肥大细胞）的肿瘤生长或肿瘤发生。
The c-kit proto-oncogene encodes a receptor tyrosine kinase that is known to play a crucial role in hematopoiesis, especially in mast cell growth and differentiation. Although a number of dominant loss-of- function mutations of c-kit gene have been well characterized in mice, rats, and humans, little is known about the c-kit mutations contributing to ligand-independent activation of the c-kit receptor tyrosine kinase (KIT). In a murine mastocytoma cell line, P-815, KIT has been found to be constitutively phosphorylated on tyrosine and activated in a ligand-independent manner. Sequencing of the whole coding region of c-kit cDNA showed that c-kit cDNA of P-815 cells carries a point mutation in codon 814, resulting in amino acid substitution of Tyr for Asp. Murine wild-type c-kit cDNA and mutant- type c-kit cDNA encoding Tyr in codon 814 were expressed in cells of a human embryonic kidney cell line, 293T. In the transfected cells, mutant-form KITTyr814 was strikingly phosphorylated on tyrosine and activated in immune complex kinase reaction regardless of stimulation with a ligand for KIT (stem cell factor), whereas tyrosine phosphorylation and activation was barely detectable in wild-form KIT. The data presented here provide evidence for a novel activating mutation of c-kit gene that might be involved in neoplastic growth or oncogenesis of some cell types, including mast cells.