Lemmens Laure, Urbach Serge, Prudent Renaud, Cochet Claude, Baldacci Giuseppe, Hughes Patrick
Institut Curie-CNRS, Unité de Genotoxicologie et Cycle Cellulaire, Université Paris Sud-XI, Batiment 110, 91405 Orsay Cedex, France.
Biochem Biophys Res Commun. 2008 Mar 7;367(2):264-70. doi: 10.1016/j.bbrc.2007.12.083. Epub 2007 Dec 26.
Of the four subunits constituting DNA polymerase delta, subunit C or p66 has been shown to mainly mediate polymerase interaction with PCNA, an auxiliary factor that greatly enhances DNA polymerase delta processivity on primed DNA templates. Here, we provide evidence that a highly conserved region located between amino acids 384 and 399 in the C-terminus of p66 is phosphorylated, most probably by Protein kinase CK2, and that another region, most probably located within the PCNA interacting domain in its extreme C-terminus, regulates its interaction with PCNA. Phosphorylation of p66 is associated with its co-localization with large subunit of DNA polymerase delta, p125, and PCNA, to the insoluble chromatin fraction at the beginning of S-phase. Taken together, the results provide evidence that concurrent phosphorylation events in p66 may positively and negatively regulate its activity and interactions with other components of the replisome during the cell cycle.
在构成DNA聚合酶δ的四个亚基中，亚基C或p66已被证明主要介导聚合酶与增殖细胞核抗原（PCNA）的相互作用，PCNA是一种辅助因子，可极大地增强DNA聚合酶δ在引发的DNA模板上的持续合成能力。在此，我们提供证据表明，p66 C末端氨基酸384至399之间的一个高度保守区域被磷酸化，最有可能是被蛋白激酶CK2磷酸化，并且另一个区域，很可能位于其极端C末端的PCNA相互作用结构域内，调节其与PCNA的相互作用。p66的磷酸化与其在S期开始时与DNA聚合酶δ的大亚基p125以及PCNA共定位于不溶性染色质部分有关。综上所述，这些结果提供了证据，表明p66中同时发生的磷酸化事件可能在细胞周期中对其活性以及与复制体其他组分的相互作用产生正向和负向调节。
