Clair T, Ally S, Tagliaferri P, Robins R K, Cho-Chung Y S
Cellular Biochemistry Section, National Cancer Institute, Bethesda, MD 20892.
FEBS Lett. 1987 Nov 30;224(2):377-84. doi: 10.1016/0014-5793(87)80488-x.
Site-selective cAMP analogs, depending on the position of their substituents on the adenine ring, selectively bind to either site 1 or site 2 of the known cAMP binding sites of protein kinase. Treatment of Harvey murine sarcoma virus-transformed NIH/3T3 cells with such site-selective analogs results in growth inhibition and phenotypic reversion, and the combination of a C-8 thio or halogen analog (site 1 selective) with an N6 analog (site 2 selective) produces a synergistic effect. We report here that the growth inhibitory effect of the analogs correlates with the nuclear translocation of the RII cAMP receptor protein, the regulatory subunit of protein kinase type II. The transformed NIH/3T3 cells contained no detectable level of RII in the nucleus, whereas nontransformed NIH/3T3 cells exhibited a high level of nuclear RII. Within 30 min after treatment of the transformed cells with the site-selective analogs, immunofluorescence against the RII protein markedly increased in the cell nucleus. The nuclear translocation of the RII cAMP receptor protein is an early event in the reverse transformation of the fibroblasts treated with site-selective cAMP analogs.
位点选择性的环磷酸腺苷（cAMP）类似物，取决于其取代基在腺嘌呤环上的位置，可选择性地结合到蛋白激酶已知的cAMP结合位点的位点1或位点2上。用此类位点选择性类似物处理哈维鼠肉瘤病毒转化的NIH/3T3细胞会导致生长抑制和表型逆转，并且C-8硫代或卤素类似物（位点1选择性）与N6类似物（位点2选择性）的组合会产生协同效应。我们在此报告，这些类似物的生长抑制作用与RII cAMP受体蛋白（蛋白激酶II型的调节亚基）的核转位相关。转化的NIH/3T3细胞在细胞核中未检测到RII水平，而未转化的NIH/3T3细胞则表现出高水平的核RII。在用位点选择性类似物处理转化细胞后的30分钟内，针对RII蛋白的免疫荧光在细胞核中明显增加。RII cAMP受体蛋白的核转位是用位点选择性cAMP类似物处理的成纤维细胞逆向转化中的早期事件。
