Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.
PLoS One. 2010 Apr 23;5(4):e10341. doi: 10.1371/journal.pone.0010341.
WRN is a multi-functional protein involving DNA replication, recombination and repair. WRN acetylation has been demonstrated playing an important role in response to DNA damage. We previously found that WRN acetylation can regulate its enzymatic activities and nuclear distribution.
METHODOLOGY/PRINCIPAL FINDING: Here, we investigated the factors involved in WRN acetylation and found that CBP and p300 are the only major acetyltransferases for WRN acetylation. We further identified 6 lysine residues in WRN that are subject to acetylation. Interestingly, WRN acetylation can increase its protein stability. SIRT1-mediated deacetylation of WRN reverses this effect. CBP dramatically increases the half-life of wild type WRN, while mutation of these 6 lysine residues (WRN-6KR) abrogates this increase. We further found that WRN stability is regulated by the ubiquitination pathway and WRN acetylation by CBP significantly reduces its ubiquitination. Importantly, we found that WRN is strongly acetylated and stabilized in response to mitomycin C (MMC) treatment. H1299 cells stably expressing WRN-6KR, which mimics unacetylated WRN, display significantly higher MMC sensitivity compared with the cells expressing wild-type WRN.
CONCLUSION/SIGNIFICANCE: Taken together, these data demonstrate that WRN acetylation regulates its stability and has significant implications regarding the role of acetylation on WRN function in response to DNA damage.
WRN 是一种多功能蛋白，参与 DNA 复制、重组和修复。WRN 的乙酰化已被证明在应对 DNA 损伤中发挥重要作用。我们之前发现，WRN 的乙酰化可以调节其酶活性和核分布。
方法/主要发现：在这里，我们研究了参与 WRN 乙酰化的因素，发现 CBP 和 p300 是 WRN 乙酰化的唯一主要乙酰转移酶。我们进一步鉴定了 WRN 中的 6 个赖氨酸残基，这些残基可被乙酰化。有趣的是，WRN 的乙酰化可以增加其蛋白质稳定性。SIRT1 介导的 WRN 去乙酰化会逆转这种效应。CBP 显著增加野生型 WRN 的半衰期，而突变这 6 个赖氨酸残基（WRN-6KR）则会消除这种增加。我们进一步发现，WRN 的稳定性受泛素化途径调节，CBP 对 WRN 的乙酰化显著降低了其泛素化。重要的是，我们发现 WRN 在受到丝裂霉素 C（MMC）处理时会强烈乙酰化和稳定。稳定表达 WRN-6KR 的 H1299 细胞（模拟未乙酰化的 WRN）与表达野生型 WRN 的细胞相比，对 MMC 的敏感性显著增加。
结论/意义：综上所述，这些数据表明，WRN 的乙酰化调节其稳定性，并对乙酰化在 WRN 功能应对 DNA 损伤中的作用具有重要意义。
