Kase Satoru, Yoshida Kazuhiko, Ohgami Kazuhiro, Shiratori Kenji, Suzuki Yukari, Nakayama Keiichi I, Ohno Shigeaki
Department of Ophthalmology and Visual Sciences, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Int J Mol Med. 2006 Mar;17(3):465-8.
It was recently demonstrated that a lack of p27(KIP1) degradation resulted in the suppression of cdc2 activity and consequent inhibition of entry into the M-phase. The aim of this study was to examine the distribution of phosphorylated p27(KIP1) on threonine 187 (T187-phospho-p27) and cdc2 in mitotic cells of human retinoblastoma, a malignant retinal neoplasm. Several T187-phospho-p27-immunopositive cells were observed in mitotic retinoblastoma cells, but not in the normal retina. Immunoreactivity for T187-phospho-p27 was located in the prophase and metaphase of mitotic tumor cells. In contrast, tumor cells in the anaphase showed no immunoreactivity for T187-phospho-p27. Nuclear expression of cdc2 was detected in many retinoblastoma cells, including mitotic cells. The immunoreactivity in mitotic cells was located in the prophase, as well as metaphase. In contrast, anaphase cells did not show immunoreactivity. Double staining demonstrated the same localization of T187-phospho-p27 and cdc2 in mitotic cells. These results suggest that p27(KIP1) interacts with cdc2 in the M-phase of human retinoblastoma cells.
最近有研究表明，p27（KIP1）降解的缺乏会导致cdc2活性受到抑制，进而抑制细胞进入M期。本研究的目的是检测人视网膜母细胞瘤（一种恶性视网膜肿瘤）有丝分裂细胞中苏氨酸187位点磷酸化的p27（KIP1）（T187-磷酸化-p27）和cdc2的分布情况。在视网膜母细胞瘤有丝分裂细胞中观察到了几个T187-磷酸化-p27免疫阳性细胞，但在正常视网膜中未观察到。T187-磷酸化-p27的免疫反应性位于有丝分裂肿瘤细胞的前期和中期。相比之下，后期的肿瘤细胞对T187-磷酸化-p27没有免疫反应性。在许多视网膜母细胞瘤细胞中检测到了cdc2的核表达，包括有丝分裂细胞。有丝分裂细胞中的免疫反应性位于前期以及中期。相比之下，后期细胞没有显示出免疫反应性。双重染色显示T187-磷酸化-p27和cdc2在有丝分裂细胞中的定位相同。这些结果表明，在人视网膜母细胞瘤细胞的M期，p27（KIP1）与cdc2相互作用。
