Sato C, Nishizawa K, Nakayama T, Hirai R, Nakamura H
Exp Cell Res. 1986 Dec;167(2):281-6. doi: 10.1016/0014-4827(86)90169-2.
Protein kinases are thought to play a key role in signal transduction and oncogenesis, but little is known about the intranuclear phosphorylation events associated with transformation. Here we report on cell cycle-dependent phosphorylation of cytoskeleton-associated 350 kD protein and the regular interchange in its location between the nucleus and cytoplasm of normal cells. Persistent intranuclear location of the phosphorylated 350 kD protein was also found throughout the cell cycle in transformed cells, as detected by immunoprecipitation of 32P-phosphorylated 350 kD protein from isolated nuclei and immunofluorescent staining with a monoclonal antibody that recognized phosphorylated site of 350 kD protein. A conditional transformed phenotype induced by a temperature-sensitive (ts) viral oncogene or a transforming growth factor was also associated with the intranuclear presence of the phosphorylated 350 kD protein. Thus the 350 kD protein seems to be a target molecule of protein kinases that are stimulated directly or indirectly by growth factors or by oncogene products in the nucleus, and appears to be a new transformation-related nuclear antigen.
蛋白激酶被认为在信号转导和肿瘤发生中起关键作用，但对于与细胞转化相关的核内磷酸化事件却知之甚少。在此，我们报告细胞骨架相关的350 kD蛋白的细胞周期依赖性磷酸化，以及其在正常细胞核与细胞质之间位置的规律性互换。通过从分离的细胞核中免疫沉淀32P标记的磷酸化350 kD蛋白，以及用识别350 kD蛋白磷酸化位点的单克隆抗体进行免疫荧光染色检测发现，在转化细胞的整个细胞周期中也能发现磷酸化的350 kD蛋白持续定位于细胞核内。由温度敏感型（ts）病毒癌基因或转化生长因子诱导的条件性转化表型也与磷酸化的350 kD蛋白在细胞核内的存在有关。因此，350 kD蛋白似乎是蛋白激酶的靶分子，这些蛋白激酶直接或间接受生长因子或核内癌基因产物刺激，并且似乎是一种新的与转化相关的核抗原。
