Proteolytic Degradation of the Yap1 Transcription Factor Is Regulated by Subcellular Localization and the E3 Ubiquitin Ligase Not4
Proteolytic Degradation of the Yap1 Transcription Factor Is Regulated by Subcellular Localization and the E3 Ubiquitin Ligase Not4
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DOI：
10.1074/jbc.m112.384719
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发表时间：
2012-08-03
影响因子：
4.8
通讯作者：
Moye-Rowley, W. Scott
中科院分区：
文献类型：
--
作者：
Gulshan, Kailash;Thommandru, Bernice;Moye-Rowley, W. Scott
酿酒酵母Yap1是一种转录调节蛋白，是氧化应激耐受的中心决定因素。该因子的活性在很大程度上受其亚细胞位置的控制。在没有氧化剂的情况下，Yap1主要位于细胞质中。在氧化剂挑战后，Yap 1在细胞核中迅速积累，并激活氧化应激耐受性所需的基因（例如硫氧还蛋白TRX 2）的表达。在这里，我们证明了Yap1降解加速响应氧化应激。Yap1的折叠方式不同，这取决于用于诱导其核定位的氧化剂，但无论其折叠状态如何，其降解方式相似。突变形式的Yap1组成型被困在细胞核中降解的氧化剂信号的情况下。降解需要蛋白质结合DNA的能力和因子氨基末端区域的结构域。蛋白酶体的抑制阻止Yap1周转。筛选各种参与泛素介导的蛋白水解的突变体，证明了核泛素连接酶Not4在Yap1降解中的重要作用。发现Not4以氧化剂刺激的方式与Yap 1结合。白色念珠菌Yap1同源物（Cap1）在氧化剂挑战后也被降解。这些数据揭示了一个新的，保守的途径，用于调节氧化应激反应，暂时限制Yap1依赖性转录激活的持续时间。
Saccharomyces cerevisiae Yap1 is a transcriptional regulatory protein that serves as a central determinant of oxidative stress tolerance. Activity of this factor is regulated in large part by control of its subcellular location. In the absence of oxidants, Yap1 is primarily located in the cytoplasm. Upon oxidant challenge, Yap1 accumulates rapidly in the nucleus where it activates expression of genes required for oxidative stress tolerance such as the thioredoxin TRX2. Here, we demonstrate that Yap1 degradation is accelerated in response to oxidative stress. Yap1 is folded differently depending on the oxidant used to induce its nuclear localization but is degraded similarly, irrespective of its folded status. Mutant forms of Yap1 that are constitutively trapped in the nucleus are degraded in the absence of an oxidant signal. Degradation requires the ability of the protein to bind DNA and a domain in the amino-terminal region of the factor. Inhibition of the proteasome prevents Yap1 turnover. Screening a variety of mutants involved in ubiquitin-mediated proteolysis demonstrated an important role for the nuclear ubiquitin ligase Not4 in Yap1 degradation. Not4 was found to bind to Yap1 in an oxidant-stimulated fashion. The Candida albicans Yap1 homologue (Cap1) also was degraded after oxidant challenge. These data uncover a new, conserved pathway for regulation of the oxidative stress response that serves to temporally limit the duration of Yap1-dependent transcriptional activation.