Radhakrishnan Senthil K, Gartel Andrei L
Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Cell Cycle. 2006 Mar;5(5):519-21. doi: 10.4161/cc.5.5.2514. Epub 2006 Mar 1.
Tumor suppressor p53 is often activated in response to DNA damage or other forms of stress, leading to either cell cycle arrest or apoptosis. Stress-induced kinases phosphorylate p53 thereby enhancing its stability, leading to an increase in transactivation of its target genes. Several different protein kinases phosphorylate p53 on multiple amino acid residues. Here, we report for the first time that Cyclin dependent kinase 9, whose well-known substrate is RNA polymerase II, can also phosphorylate p53. Specifically, Ser33 on the N-terminus and, Ser315 and Ser392 on the C-terminus of p53 were found to be phosphorylated. The precise biological role of this phosphorylation remains to be elucidated.
肿瘤抑制因子p53通常在DNA损伤或其他形式的应激反应中被激活，导致细胞周期停滞或凋亡。应激诱导的激酶使p53磷酸化，从而增强其稳定性，导致其靶基因的转录激活增加。几种不同的蛋白激酶在多个氨基酸残基上使p53磷酸化。在此，我们首次报道细胞周期蛋白依赖性激酶9（其著名的底物是RNA聚合酶II）也能使p53磷酸化。具体而言，发现p53 N端的Ser33以及C端的Ser315和Ser392被磷酸化。这种磷酸化的确切生物学作用仍有待阐明。
