THE HUMAN C-FPS/FES GENE-PRODUCT EXPRESSED ECTOPICALLY IN RAT FIBROBLASTS IS NONTRANSFORMING AND HAS RESTRAINED PROTEIN-TYROSINE KINASE-ACTIVITY
THE HUMAN C-FPS/FES GENE-PRODUCT EXPRESSED ECTOPICALLY IN RAT FIBROBLASTS IS NONTRANSFORMING AND HAS RESTRAINED PROTEIN-TYROSINE KINASE-ACTIVITY
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DOI：
10.1128/mcb.8.2.578
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发表时间：
1988-02-01
影响因子：
5.3
通讯作者：
PAWSON, T
中科院分区：
文献类型：
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作者：
GREER, PA;MECKLINGHANSEN, K;PAWSON, T
含有人c-fps/fes原癌基因位点的13-内切酶EcoRI基因组限制性片段在Cos-1猴细胞中瞬时表达，并在Rat-2成纤维细胞中稳定表达。在这两种情况下，人c-fps/fes指导合成的92千道尔顿蛋白酪氨酸激酶（p92 c-fes）与以前确定的酪氨酸激酶与抗fps抗血清，这是特异性表达在人骨髓细胞。转染的Rat-2细胞含有比在人白血病细胞中发现的多约50倍的人p92 c-fes，其形态保持正常，并且不能在软琼脂中生长。在该表型正常系中p92 c-fes的合成超过了在v-fps转化的Rat-2系中P130 gag-fps癌蛋白的合成。尽管这种升高的表达，人p92 c-fes诱导细胞磷酸酪氨酸没有实质性增加，本身没有磷酸化酪氨酸。相反，92 c-fes免疫沉淀从这些大鼠-2细胞或表达作为一个酶活性片段在大肠杆菌中从c-fps/fes cDNA催化酪氨酸磷酸化的活性类似的v-fps/fes多肽。因此，当在大鼠-2成纤维细胞中异位过表达时，p92 c-fes不转化。这种转化活性的缺乏与对体内正常c-fps/fes产物的激酶活性施加的限制相关，而v-fps/fes癌蛋白的激酶活性明显升高，这表明宿主细胞内的调节相互作用改变了fps/fes蛋白的功能，并通常抑制其致癌潜力。
A 13-kilobase EcoRI genomic restriction fragment containing the human c-fps/fes proto-oncogene locus was expressed transiently in Cos-1 monkey cells and stably in Rat-2 fibroblasts. In both cases, human c-fps/fes directed synthesis of a 92-kilodalton protein-tyrosine kinase (p92c-fes) indistinguishable from a tyrosine kinase previously identified with anti-fps antiserum which is specifically expressed in human myeloid cells. Transfected Rat-2 cells containing approximately 50-fold more human p92c-fes than is found in human leukemic cells remained morphologically normal and failed to grow in soft agar. Synthesis of p92c-fes in this phenotypically normal line exceeded that of the P130gag-fps oncoprotein in a v-fps-transformed Rat-2 line. Despite this elevated expression, human p92c-fes induced no substantial increase in cellular phosphotyrosine and was not itself phosphorylated on tyrosine. In contrast, 92c-fes immunoprecipitated from these Rat-2 cells or expressed as an enzymatically active fragment in Escherichia coli from a c-fps/fes cDNA catalyzed tyrosine phosphorylation with an activity similar to that of v-fps/fes polypeptides. Thus, p92c-fes is not transforming when ectopically overexpressed in Rat-2 fibroblasts. This lack of transforming activity correlated with a restriction imposed on the kinase activity of the normal c-fps/fes product in vivo which is apparently lifted for v-fps/fes oncoproteins, suggesting that regulatory interactions within the host cell modify fps/fes protein function and normally restrain its oncogenic potential.