【摘要】 以ＬＡ９０细胞（ＲＳＶ温度敏感突变株ＬＡ９０转化的小鼠成纤维细胞〕为模型，研究了二酰甘油（ＤＧ）－蛋白激酶Ｃ（ＰＫＣ）信使系统在细胞转化中的作用。通过免疫沉淀法观察到ＬＡ９０细胞在允许温度（３３℃）时具有很高的ｐｐ６０ｖ－ｓｒｃ激酶活性，远高于非允许温度（３９℃），当从３９℃转至３３℃１０分钟，激酶活性就已显著升高。同时运用３Ｈ－甘油掺入并结合板层析分离方法和酶活性测定，发现ＬＡ９０细胞中ＤＧ含量和ＰＫＣ活性在３３℃条件下高于３９℃，当由３９℃转至３３℃１０分钟，细胞内ＤＧ含量和ＰＫＣ活性均明显增加。我们进一步探讨了ＰＫＣ活性与癌基因ｖ－ｓｅｒ、ｐ５３基因表达的相关性，实验表明，ＰＫＣ的激活剂ＴＰＡ可刺激３９℃条件下的ＬＡ９０细胞中ｖ－ｓｒｅ和ｐ５３基因表达，ＰＫＣ选择性抑制剂Ｈ７可抑制３３℃条件下ＬＡ９０细胞中ｖ－ｅｒｃ和ｐ５３基因表达。看来，ｐｐ６０ｖ－ｓｒｃ可通过刺激磷脂酰肌醇（ＰＩ）代谢激活ＤＧ－ＰＫＣ（ｄｉａｃｙｌｇｌｙｃｅｒｏｌ－ｐｒｏｔｅｉｎｋｉｎａｓｅＣ）信使系统，后者通过某种途径调控ｖ－ｓｒｃ和ｐ５３等癌基因之表达。因此ＤＧ－ＰＫＣ信使系统可能是ｐｐ６０ｖ－ｓｒｃ转化细胞及被转化细胞维持转?更多还原

【Abstract】 LA90 Cells which are mouse fibroblasts transformed by a is mutant of Rous sarcoma virus(RSV) were used as the model to investigate the effect of DG-PKC pathway in the cell transformation. The kinase activity of pp60v-src, increased markedly within 10 minutes in LA90 Cells, when the temperature was shifted n from 39℃ to 33℃. By using 3H-glycerol incorperation, TLO analysis and enzyme assay, we demonstrated that the DG level and PKC activity of LA90 Cells at the Permissive temperature (33℃) were higher than those of LA90 Cells at the nonpermissive temperature (39℃).The DG level increased 94% within 10 minutes and the PKC activity increased significantly within 10 minutes in LA90 Cell8, when the temperature was shifted from 39℃ to 33℃.The selective inhibitor-H7 and aetivator-TPA for PKC can inhibit and stimulate the expression of v-sre and p53 genes respectively. Because PP60v-src, has been found to phosphorylate PI and PIP, the elevated DG level and the increase of PKC activity may come from the enhanced PI turnover. The DG regulation of PKC activity may Play an important role in the control of v-sre and P53 genes expression. It seems that high level of DG and PKC may be a key event in the regulation of cell transformation and in keeping the transformed phenotype of the Cell.更多还原