Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
J Exp Bot. 2012 May;63(8):2971-83. doi: 10.1093/jxb/ers002. Epub 2012 Feb 13.
Proliferating cell nuclear antigen (PCNA) is post-translationally modified in yeast and animal cells. Major studies carried out in the last decade have focused on the role of sumoylated and ubiquitinated PCNA. Using different approaches, an interaction between plant PCNA and SUMO both in vivo and in bacteria has been demonstrated for the first time. In addition, identical sumoylation patterns for both AtPCNA1 and 2 were observed in bacteria. The plant PCNA sumoylation pattern has been shown to differ significantly from that of Saccharomyces cerevisiae. This result contrasts with a common opinion based on previous structural analysis of yeast, human, and plant PCNAs, which treats PCNA as a highly conserved protein even between species. Analyses of AtPCNA post-translational modifications using different SUMO proteins (SUMO1, 2, 3, and 5) revealed similar modification patterns for each tested SUMO protein. Potential target lysine residues that might be sumoylated in vivo were identified on the basis of in bacteria AtPCNA mutational analyses. Taken together, these results clearly show that plant PCNA is post-translationally modified in bacteria and may be sumoylated in a plant cell at various sites. These data open up important new perspectives for further detailed studies on the role of PCNA sumoylation in plant cells.
增殖细胞核抗原（PCNA）在酵母和动物细胞中经过翻译后的修饰。过去十年的主要研究集中在 SUMO 化和泛素化 PCNA 的作用上。通过不同的方法，首次证明了植物 PCNA 与 SUMO 在体内和细菌中的相互作用。此外，在细菌中观察到 AtPCNA1 和 2 的相同 SUMO 化模式。植物 PCNA 的 SUMO 化模式与酿酒酵母的差异非常显著。这一结果与之前基于酵母、人类和植物 PCNAs 的结构分析的普遍观点形成了对比，该观点将 PCNA 视为一种高度保守的蛋白质，即使在物种之间也是如此。使用不同的 SUMO 蛋白（SUMO1、2、3 和 5）对 AtPCNA 的翻译后修饰进行分析，结果表明每个测试的 SUMO 蛋白都具有相似的修饰模式。基于细菌中的 AtPCNA 突变分析，确定了可能在体内 SUMO 化的潜在靶赖氨酸残基。综上所述，这些结果清楚地表明，植物 PCNA 在细菌中经过翻译后的修饰，并且可能在植物细胞中在不同的位点被 SUMO 化。这些数据为进一步研究 PCNA SUMO 化在植物细胞中的作用提供了重要的新视角。
