Hupp T R, Lane D P
Department of Biochemistry, Dundee University, Scotland.
J Biol Chem. 1995 Jul 28;270(30):18165-74. doi: 10.1074/jbc.270.30.18165.
Post-translational modification of a carboxyl-terminal negative regulatory domain in vitro by either casein kinase II or protein kinase C allosterically activates the latent sequence-specific DNA binding function of p53. Reported here is a biochemical approach to determine the types of signaling pathways and enzymes that are involved in p53 activation in cells. Using a novel chromatographic method, we have been able to separate three distinct biochemical forms of p53 that have been synthesized in vivo; two are in an activated state, and one is in a latent state for sequence-specific DNA binding. The two activated forms of p53 appear to be controlled individually by either a constitutive or a UV-inducible signaling pathway. p53 lacking the COOH-terminal casein kinase II site (p53 delta 4) was characterized biochemically and used to determine the affects of deletion of the casein kinase II motif on the production of the two activated forms of p53 in vivo. As observed with full-length p53, the production of two distinct chromatographic forms of activated p53 delta 4 occurs in vivo, indicating that p53 activation can occur through a casein kinase II-independent pathway and suggesting that two other factors are involved in activation of p53 in vivo.
酪蛋白激酶II或蛋白激酶C在体外对p53羧基末端负调控域进行的翻译后修饰可别构激活p53潜在的序列特异性DNA结合功能。本文报道了一种生化方法，用于确定细胞中参与p53激活的信号通路和酶的类型。使用一种新型色谱方法，我们能够分离出体内合成的三种不同生化形式的p53；两种处于激活状态，一种处于序列特异性DNA结合的潜伏状态。p53的两种激活形式似乎分别由组成型或紫外线诱导型信号通路单独控制。缺乏COOH末端酪蛋白激酶II位点的p53（p53δ4）经过生化表征，并用于确定酪蛋白激酶II基序缺失对体内两种激活形式的p53产生的影响。正如全长p53所观察到的那样，体内会产生两种不同色谱形式的激活型p53δ4，这表明p53激活可以通过酪蛋白激酶II非依赖性途径发生，并表明体内p53激活还涉及另外两个因素。
