Venetian Institute of Molecular Medicine (VIMM), Via G. Orus, 2, 35129, Padova, Italy.
Cell Mol Life Sci. 2010 Apr;67(7):1105-18. doi: 10.1007/s00018-009-0236-7. Epub 2009 Dec 30.
The ability of three isoforms of protein kinase CK1 (alpha, gamma(1), and delta) to phosphorylate the N-terminal region of p53 has been assessed using either recombinant p53 or a synthetic peptide reproducing its 1-28 sequence. Both substrates are readily phosphoylated by CK1delta and CK1alpha, but not by the gamma isoform. Affinity of full size p53 for CK1 is 3 orders of magnitude higher than that of its N-terminal peptide (K (m) 0.82 muM vs 1.51 mM). The preferred target is S20, whose phosphorylation critically relies on E17, while S6 is unaffected despite displaying the same consensus (E-x-x-S). Our data support the concept that non-primed phosphorylation of p53 by CK1 is an isoform-specific reaction preferentially affecting S20 by a mechanism which is grounded both on a local consensus and on a remote docking site mapped to the K(221)RQK(224) loop according to modeling and mutational analysis.
已使用重组 p53 或复制其 1-28 序列的合成肽来评估三种蛋白激酶 CK1（α、γ（1）和δ）同工型对 p53 N 端区域的磷酸化能力。两种底物都可被 CK1δ和 CK1α轻松磷酸化，但不能被γ同工型磷酸化。全长 p53 与 CK1 的亲和力比其 N 端肽高 3 个数量级（K（m）0.82 μM 对 1.51 mM）。首选靶标是 S20，其磷酸化严重依赖于 E17，而 S6 不受影响，尽管显示出相同的共识（E-x-x-S）。我们的数据支持以下概念：CK1 对 p53 的非启动磷酸化是一种同工型特异性反应，通过一种机制优先影响 S20，该机制既基于局部共识，也基于根据建模和突变分析映射到 K（221）RQK（224）环的远程对接位点。
