Imai Y, Kakinoki Y, Takizawa N, Nakamura K, Shima H, Kikuchi K
Section of Biochemistry, Institute of Immunological Science, Hokkaido University, Kita-Ku, Sapporo 060-0815, Japan.
Int J Oncol. 1999 Jan;14(1):121-6. doi: 10.3892/ijo.14.1.121.
Activities of nuclear type 1 protein phosphatase (PP1) were significantly elevated in human HepG2 and rat AH13 hepatoma cells compared with primary cultured hepatocytes. We examined and compared the nuclear PP1 activities during the cell cycle between synchronized HepG2 cells and HGF-stimulated hepatocytes. Nuclear PP1 activity was significantly and more elevated at the G1/S transition in hepatoma cells compared with hepatocytes, although the amounts of PP1 isoforms remained constant. On the contrary, it was found that the basal levels of nuclear PP1 activity were significantly higher in hepatoma cells and that the amounts of PP1alpha and PP1delta were dramatically increased in the nuclear fraction of hepatoma cells.
与原代培养的肝细胞相比，人肝癌细胞系HepG2和大鼠肝癌细胞系AH13中1型核蛋白磷酸酶（PP1）的活性显著升高。我们检测并比较了同步化的HepG2细胞和肝细胞生长因子（HGF）刺激的肝细胞在细胞周期中的核PP1活性。与肝细胞相比，肝癌细胞在G1/S期转换时核PP1活性显著升高且升高幅度更大，尽管PP1亚型的量保持不变。相反，发现肝癌细胞核PP1活性的基础水平显著更高，并且肝癌细胞核组分中PP1α和PP1δ的量显著增加。
